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Harmful Algae 6 (2007) 29–47

The first description of the potentially toxic dinoflagellate,

Alexandrium minutum in Hunts Bay,

Kingston Harbour, Jamaica

Emma R. Ranston a,*, Dale F. Webber a, Jacob Larsen b

a Department of Life Sciences, University of The West Indies, Mona Campus, Mona, Kingston 7, Jamaica, West Indiesb IOC-DANIDA, Science and Communication Centre on Harmful Algae,

University of Copenhagen, Øster Farimagsgade 2D, DK-1353 Copenhagen K., Denmark

Received 2 February 2006; received in revised form 20 April 2006; accepted 30 May 2006

Abstract

The occurrence and morphology of the potentially toxic dinoflagellate species Alexandrium minutum found for the first time in

Jamaica, were examined and described by light and scanning electron microscopy. Classical morphological examinations of whole

cells, the thecal plate pattern of intact cells and more importantly the structure of individual thecal plates of squashed cells, were

conducted in an attempt to positively identify the species. Characteristics such as a tear-drop shaped apical pore plate with a comma-

shaped apical pore and no anterior attachment pore; a narrow sixth precingular plate; a narrow anterior sulcal plate longer than or

approximately as long as it is wide; and a posterior sulcal plate wider than long, confirmed the Jamaican species as A. minutum. This

dinoflagellate which produces potent neurotoxins responsible for paralytic shellfish poisoning (PSP) in humans in many parts of the

World, as well as mass mortality of various marine flora and fauna, was identified in water samples collected during an extensive

bloom of the species in the brackish to saline water body of Hunts Bay, an estuarine arm of Kingston Harbour, Jamaica in August

1994. The highest cell concentration was 4.6 � 105 cells l�1, a concentration which far exceeds acceptable concentrations

(<103 cells l�1) of PSP-toxin producing A. minutum in several countries including: Spain and Denmark. No PSP human symptoms

were reported during the bloom; however it was accompanied by a large kill of small pelagic fish extending across a third of the bay.

Since then, smaller blooms of A. minutum have occurred with the most recent in February and April 2004. Hunts Bay is an important

fishing, shrimping and to some extent oyster/mussel collection area and provides an important source of livelihood and food for

many fishermen in nearby fishing communities as well as an important source of food for members of other communities. Although

there are no known records of human illness due to PSP in Jamaica, the occurrence and blooming in Jamaican waters of this

potentially toxic dinoflagellate, is great cause for concern.

# 2006 Elsevier B.V. All rights reserved.

Keywords: Alexandrium minutum; First description; Hunts Bay; Kingston Harbour; Jamaica

* Corresponding author at: P.O. Box 34, Red Hills P.O., St. Andrew,

Jamaica, West Indies. Tel.: +876 944 4624; fax: +876 944 4324.

E-mail address: emma.ranston@uwimona.edu.jm (E.R. Ranston).

1568-9883/$ – see front matter # 2006 Elsevier B.V. All rights reserved.

doi:10.1016/j.hal.2006.05.006

1. Introduction

Alexandrium minutum was first described in Alex-

andria, Egypt (Halim, 1960). It has also been found in

Europe (Montresor et al., 1990), Asia (Chang et al.,

1997), Australia and North America (Hallegraeff et al.,

1988, 1991) where it can form blooms in estuarine

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–4730

waters (Hallegraeff et al., 1988), eutrophic brackish

lagoons (Giacobbe et al., 1996) and aquaculture ponds

(Yoshida et al., 2000).

A. minutum is one of the at least nine toxic species of

the Alexandrium genus, known to be responsible for

PSP in many parts of the world including South

Australia (Hallegraeff et al., 1988) and France (Erard-

Le Denn, 1991; Belin, 1993). Dinoflagellates such as A.

minutum are therefore receiving increasing attention

due to the public health risk they pose and the economic

impacts they have on fisheries and aquaculture

developments (Hallegraeff et al., 1991).

The coastal waters of Jamaica have been the site of

several confirmed and unconfirmed red tides over the

years, sometimes accompanied by fish kills (Steven,

1966; Goodbody, 1970; Wade, 1971; Simmonds, 1997).

Kingston Harbour, the principal port of the island

(Fig. 1), has been the major site of several red tides,

which according to Goodbody (1970), are due to

blooms of various diatoms and dinoflagellates, many of

which have not been identified. More recent studies

such as Simmonds (1997) have identified the numeri-

cally important red tide organisms in Kingston Harbour

as Ceratium furca, Trichodesmium spp., Cylindrotheca

closterium and Cyclotella sp.

Kingston Harbour is an extensive harbour located on

the south coast of the island of Jamaica in the Caribbean

Sea between 17857.00 and 17857.50N and 76848.20 and

Fig. 1. Map of Kingston Harbour with major features.

76848.50W (Fig. 1). With a total surface area of

approximately 51 km2 (Wade et al., 1972), Kingston

Harbour has developed as a major international trans-

shipment centre for the Caribbean. The harbour is

bounded on the north by Kingston, the larger of the two

cities of the island, with a population of about 716,000

(STATIN, 2000). A narrow strip of land, the Palisadoes

Spit, forms the southern boundary and at the south-

western corner, the harbour communicates with the

Caribbean Sea via an opening approximately 3.2 km

wide (Goodbody, 1970). The harbour has been divided

into four major regions based on bathymetry; Hunts

Bay, the Upper Basin, Inner Harbour and Outer Harbour

(Goodbody, 1970) (Fig. 1).

In August 1994, an extensive red tide occurred

throughout Hunts Bay accompanied by a large kill of

small pelagic fish extending across a third of the bay.

The organism creating the bloom was found to be a

small dinoflagellate that at the time could not be

identified to the species level due to lack of expertise.

The organism was subsequently identified as A.

minutum during preliminary investigations of the bloom

cells at an IOC-DANIDA training course on the

Taxonomy and Biology of Harmful Marine Microalgae

in Denmark in 1996.

Ranston (1998) observed that the A. minutum like

cells were consistent members of the phytoplankton

community of Hunts Bay during a 14-month water

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–47 31

quality study of the area extending from December

1993 to February 1995. In February 2004, another

extensive red tide was observed throughout the bay with

previously observed A. minutum like cells dominating.

A smaller bloom of the species was reported in April

2004; however this occurred outside of Hunts Bay along

a section of the northern shoreline of Kingston Harbour.

It is not known whether any illnesses were associated

with the previous and more recent blooms of this

species.

Countries such as Jamaica which experience blooms

of potentially toxic species and lack historical records of

these species can protect and prepare themselves from

potential problems through adequate species identifica-

tion, thus allowing scientists and officials to project

potential impacts to public health, aquaculture and

coastal community economy (Steidinger et al., 1989).

The main aim of this research was thus to confirm the

specific identity of the Alexandrium species in Hunts

Bay by examination and description of the morpholo-

gical characteristics of the cells and comparison with

classical taxonomical descriptions of Alexandrium,

such as Balech (1989, 1995). This paper therefore

describes the morphology of A. minutum discovered for

the first time in Jamaican coastal waters.

2. Materials and methods

2.1. Study site description

Hunts Bay is a relatively shallow, semi-enclosed arm

of the Kingston Harbour (Fig. 1), with an average depth

of about 2.4 m and an area of approximately 6.5 km2

(Ranston and Webber, 2003). The bay has a soft, black,

highly anoxic mud bottom and receives fresh water

discharges from two rivers: the Rio Cobre and the

Duhaney Rivers, and from two major gullies – the Jew

and Sandy Gullies (Fig. 1).

The Rio Cobre, one of the largest rivers of Jamaica,

drains major sugar cane fields and other agricultural

lands to the west of Hunts Bay and receives a number of

industrial and municipal discharges (Fig. 2). The

Duhaney River and Jew Gully pass through major

industrial sectors to the north and north-east of the bay,

respectively, and the Sandy Gully drains a very large

section of the residential area of the city of Kingston

which lies to the north of the harbour (Fig. 1). Near the

west-south-western shore of the bay, a small sewage

disposal culvert, the Portsmouth Sewage outfall, directs

semi-treated sewage into the bay (Fig. 2).

With all this nutrient input, the area has been

described as one under severe ecological stress,

exhibiting all the typical characteristics of a eutrophic

body of water (Wade, 1976), which are known to

encourage the development of red tides (Lam and Yip,

1990). Ranston (1998) confirmed increasing eutrophic

conditions in Hunts Bay and reported observing

obnoxious red tides occasionally accompanied by fish

kills, throughout the bay, during routine sampling of the

area over a 14-month period.

Hunts Bay is characterized by a water column

stratified into a fresh to brackish water surface layer, due

to freshwater input from the rivers and gullies, and a

saline deeper layer. The surface waters are often

supersaturated, high in nutrient concentrations, phyto-

plankton biomass and abundance, while deeper water is

characterized by oxygen deficiency, lower nutrient

concentrations and lower phytoplankton biomass and

abundance (Ranston and Webber, 2003).

Hunts Bay used to be a very productive and

important fishing and shrimping ground and also served

as a nursery area for young commercial species that are

caught in the open sea (Goodbody, 1970). The

decreasing water quality of the area over the years

has contributed to a drastic reduction of the fish and

shrimp populations of the bay. At present all that

remains is a small shrimping industry and an even

smaller fishery for bait and other small fish throughout

the bay, resulting in general hardship for fishermen of

the surrounding communities. Despite this decline,

Hunts Bay is still an important fishing, shrimping and to

a lesser extent, oyster/mussel collection area and still

functions to some extent as a nursery area for fish and

shrimp, as well as a feeding area for dolphins during the

beginning of each year. Everyday up to 30 fishing

vessels can be seen in the bay engaged in line and net

fishing, as well as the setting of fish and crab pots. The

small pelagic fish caught in the area are used as bait to

catch larger fish out in the open ocean. Some fishermen

collect and sell the various species of oysters and

mussels that grow on the mangrove roots surrounding

the bay. Hunts Bay is thus an important source of

livelihood for the many fishermen in the area, an

important feeding and nursery area for fish, shrimp and

marine mammals, and an important source of food for

the surrounding communities.

2.2. Sampling station locations

The A. minutum blooms coincided with routine water

monitoring exercises being conducted in Hunts Bay in

August 1994 and February 2004. Quantitative and

qualitative bloom samples were therefore collected at

the same stations established for the monitoring

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–4732

Fig. 2. Map of Hunts Bay showing its major features and location of sampling stations.

exercises. These stations comprised nine sites (Fig. 2),

each with two sampling depths, one in each water layer,

(surface, 0 m and deep, 2–5 m) with the exception of

station 1, which was too shallow (1 m) for a deeper

sampling depth.

Each station was strategically positioned such that

the general area of the bay was sampled, but more

importantly to allow the monitoring of the various fresh

water inflows (point sources) to the bay. Five stations

(1–3, 5 and 6) were located at the mouth of the fresh

water inflows to the bay (Fig. 2). One station (4) was

located in the middle of the bay, two stations (7 and 8)

were located near an area of mangrove swamp and a

small fishing village, respectively, and station 9 was

located at the mouth of the bay, just outside the

causeway bridge and the point of outflow of Hunts Bay

water into Kingston Harbour (Fig. 2).

2.3. Field procedures

Measurements of temperature, salinity and dissolved

oxygen were made in situ using a Hydrolab Datasonde 4

water quality multiprobe HL002080 at the surface and

at depth with simultaneous collection of quantitative

and qualitative phytoplankton samples.

Quantitative samples of planktonic microalgae

constituting the blooms were collected at each sampling

site using a 6 l Niskin whole water bottle sampler.

Samples were collected just below the surface and at a

depth between 2 and 5 m depending on the depth of the

sample site. An aliquot of each whole water sample was

collected in a 230 ml opaque plastic bottle containing

3 ml of neutral Lugol’s iodine solution for immediate

fixing and staining of the microalgal cells for later

identification and enumeration (Steidinger, 1979).

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–47 33

Qualitative concentrated samples (net samples) of

phytoplankton were collected by hauling and towing a

20 mm plankton net through the water at each sampling

site. A vertical haul was conducted by gently lowering

the net to a point just above the seafloor and drawing the

net several times up through the water column until the

water in the net became unclear or coloured by the

concentrated algae. A horizontal surface tow was

conducted by allowing the net to sink below the water

surface followed by slow towing in a circular path

behind the boat for about 2 min. About 25 ml of one of

these samples was collected into a bottle and stored in a

cool, dark igloo as a live sample until analysis. Each net

sample was washed into a 230 ml opaque plastic bottle

containing 3 ml of neutral Lugol’s iodine solution,

using water in a spray bottle collected from each site.

Preserved qualitative and quantitative plankton samples

were stored in a cool dark area until analysis was

possible.

2.4. Laboratory procedures

2.4.1. Preliminary identification and enumeration

procedures

On return to the lab sub-samples of the live and

preserved planktonic net samples were observed on a

microscope slide using a Leitz Wetzlar Dialux 20 EB

compound microscope (model no. 020-452.008), in an

attempt to identify the dominant species of the bloom.

Quantitative determination of the species constitut-

ing the bloom was conducted using the Utermohl

method (Utermohl, 1958). Lugol’s preserved quantita-

tive samples were gently homogenised by inversion and

a 5 ml aliquot of each sample was made up to 10 ml

with filtered seawater in a 10 ml settling chamber. The

chambers were left to stand overnight to allow settling

of the phytoplankton cells before examination. Settled

samples were examined using a Leitz Labovert (model

no. 020-435.025) inverted microscope. Thirty random

fields of view of each settled sample were examined to

remove the edge effect in the settling of phytoplankton

cells (Sandgren and Robinson, 1984). The phytoplank-

ton in these thirty fields were identified and enumerated

at 320� and then each settled sample was fully scanned

at 100� to ensure that no phytoplankton species was

overlooked.

2.4.2. Confirmatory identification and microscopy

procedures

2.4.2.1. Scanning electron microscopy. Cells for elec-

tron microscopy were processed at the Electron

Microscopy Laboratory of the Botanical Institute,

Copenhagen University, using the following proce-

dures. Lugol’s preserved net samples of the bloom were

filtered directly on to a Nuclepore polycarbonate filter

by gravity filtration using a Swinnex filterholder.

Gravity filtration was used to thoroughly wash the

filtered samples with distilled water in order to get rid of

salt in the samples. After washing, samples were

chemically dehydrated using acidified 2,2-dimethox-

ypropane (DMP) (three drops 1N HCl to 25 ml DMP)

for a 10 min period. This dehydration process was

repeated and followed by critical point drying in which

the dehydration liquid in the samples was replaced by

liquid carbon dioxide, which was then vaporized. The

dried material on the filters was transferred on to a

double-sided adhesive carbon disc mounted on an SEM

stub. The material was coated with a thin layer of gold–

palladium applied by a sputtering process before

viewing using a scanning electron microscope. Electron

micrographs of the bloom cells were taken using a

camera attached to the microscope.

2.4.2.2. The squash technique. The squashing method

(Steidinger, 1979) was used to separate the thecal plates

of the bloom cells, allowing each plate to be observed

and used to aid in confirming the identity of the species.

A drop of a net sample from the bloom was placed on

a microscope slide and covered with a coverslip, gently

removing any excess seawater with a small piece of

blotting paper. The sample was observed using a Leitz

Wetzlar Dialux 20 EB compound microscope and a

Canon Power Shot G6 digital camera was used to

photograph the intact cells at 100� and 400� in an

attempt to determine the identity of the cells based on

size, shape and general morphological features.

A drop of 5% sodium hypochlorite (commercial

bleach) solution (1:1 mixture of sodium hypochlorite

and distilled water) was placed along a margin of the

coverslip and allowed to run under and across by

placing a small piece of blotting paper under the

opposite coverslip margin. A drop of neutral Lugol’s

solution was added in a similar manner in order to stain

the thecal plates. The cells were located under the

microscope and squashed by applying firm but gentle

pressure on the coverslip using a dissecting needle.

Individual thecal plates were identified with the aid

of descriptive and taxonomic references, with the

principal references being Balech (1989, 1995). Thecal

plates were viewed at 400� and 1000� with the aid of

immersion oil and photographs of these plates were

taken to show their morphological characteristics and

aid in the confirmation of the identity of the

dinoflagellate cells.

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–4734

3. Results and discussion

3.1. Qualitative and quantitative analyses

The phytoplankton bloom that occurred in August

1994 in Hunts Bay was bright orange in colour and

concentrated in the fresh to brackish water surface layer

of the bay. The bloom was accompanied by a large kill

of small pelagic fish belonging to the clupeid and

carangid groups, which extended across approximately

2 km2 of the bay and average salinity, temperature and

dissolved oxygen concentrations of 11 ppt, 26.5 8C, and

6.50 mg l�1, respectively.

Qualitative analysis of the phytoplankton in the

bloom samples revealed that the samples were

dominated by a dinoflagellate belonging to the genus

Alexandrium, which occurred along with a few other

dinoflagellate and flagellate species. Preliminary exam-

inations of the Alexandrium cells led to the subsequent

identification of the species as A. minutum.

Quantitative analyses found that the highest cell

concentration of this species in the bloom was

4.6 � 105 cells l�1, a concentration which far exceeds

acceptable concentrations of PSP-toxin producing A.

minutum in several countries. In the Balearic Islands of

Spain, cell concentrations reaching 103 cells l�1 result

in intensified monitoring and closure of shellfishery

areas (Anderson, 1996) while in Denmark, a concen-

tration as low as 500 cells l�1 is considered to be the

maximum concentration for closing or imposing special

restrictions on shellfisheries (Anderson, 1996).

3.2. Species description and identification

The genus Alexandrium is notably homogenous with

the exception of a few species and lacks conspicuous

elements, frequent in other genera such as apical horns

and spines, which help to distinguish among species

(Balech, 1995). It is therefore necessary to conduct

extremely detailed observations in order to identify

Alexandrium cells to the species level, a process not

necessary for most dinoflagellates. Confirmation of the

identity of A. minutum cells in the red tide samples was

therefore based on examination of the general cell

morphology including characteristics such as size and

shape and more importantly, thecal plate pattern of

intact cells and the morphology of individual thecal

plates of squashed cells.

3.2.1. General morphology

Cells of this species were solitary and small in size, a

little longer than wide (Fig. 3A), with lengths ranging

from 18 to 31.5 mm (mean length � S.D. = 23.6 �2.11 mm) and widths ranging from 15.3 to 23.2 mm

(mean width � S.D. = 18.55 � 1.52 mm). These dimen-

sions are similar to those recorded by Balech (1989), who

reported thecae of the species ranging in length from 17

to 29 mm, with most ranging from 21 to 26 mm. Balech

(1995) reported that the width of A. minutum equals the

length, sometimes being larger but, more often, some-

what smaller, as observed for the Jamaican specimens.

Size is a secondary characteristic, as evidenced by the

large variations within certain species, however some

species such as A. minutum are differentiated by their

normally small size (Balech, 1995), as observed for the

Jamaican specimens.

Shape is an important taxonomic character although

it can be considerably altered by environmental

conditions, sexual reproductive stages such as zygotes,

small changes in position of the specimen, coverslip

pressure and adherence of the specimen to the glass

(Balech, 1995). The shape of the cells matched descrip-

tions put forward by Balech (1989, 1995) and varied

from irregularly oval to elliptical in dorsal view,

with roughly equal epitheca and hypotheca in length

(Fig. 3B). The epitheca varied in shape from hemi-

elliptical to almost hemispherical in both ventral

and dorsal views (Fig. 3B and C), while the shape of

the hypotheca ranged from hemielliptical in dorsal

view (Fig. 3B) to hemielliptical, with oblique antapical

flattening created by the sulcus, in ventral view

(Fig. 3C).

No spines, or horns were present and plate

ornamentation in the form of fairly strong, coarse,

irregular reticulations were observed on the hypo-

theca (Fig. 3D and E). The epitheca lacked any

obvious form of ornamentation and was therefore

smooth in comparison to the hypotheca (Fig. 3D).

Balech (1995) described A. minutum as typically

having the beginning of irregular sculpture rather than

the distinct, coarse reticulations observed in the

Jamaican specimens, but the degree of reticulation

was variable, possibly due to external factors such as

environmental conditions. He reported strong and true

reticulation in the hypotheca and barely perceptible

reticulation in the epitheca of Italian specimens of A.

minutum from the Gulf of Naples, which was similar

to that observed in the Jamaican specimens. Mon-

tresor et al., 1990 also described similar heavy

reticulation of hypothecal plates in specimens from

the Tyrrhenian Sea.

Each cell had a median cingulum that was deeply

excavated, left-handed, without lists and descending

one cingular width (c in Fig. 3F). The cingulum met a

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–47 35

Fig. 3. General morphology of Alexandrium minutum: (A) Light micrograph (LM) of neutral Lugol’s iodine preserved cells; (B) LM of dorsal view

of cell; (C) LM of ventral view of cell; (D) LM of bleached/Lugol’s iodine stained cell showing smooth epithecal plates and reticulated hypothecal

plates; (E) SEM view of cell showing reticulated hypotheca and short projections of the sulcal lists (sl); (F) LM of ventral view of cell showing left-

handed, descending cingulum (c) meeting a wide sulcus (s). Scale bars = 20 mm.

wide sulcus with narrow lists on the ventral side of the

cell (s in Fig. 3F). These lists were difficult to detect,

however some cells when viewed at particular angles

showed short projections of the lists beyond the antapex

(sl in Fig. 3E), which according to Balech (1995)

sometimes appear as false spines.

3.2.2. Thecal plate morphology

The plate formula of the Jamaican specimens of A.

minutum was determined to be Po, 40, 600, 6C, 5000, 20000

and 8S. This formula was based on visible plates and

does not include two very small accessory plates (1 mm

long or shorter) that occur in the sulcus and are very

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–4736

Fig. 4. Line diagrams showing thecal plate morphology of Jamaican specimens of Alexandrium minutum: (A) ventral view of cell showing the

location of the sulcal plates: anterior sulcal plate (S.a.), posterior sulcal plate (S.p.), left anterior sulcal plate (S.s.a.), right anterior sulcal plate

(S.d.a.), left posterior sulcal plate (S.s.p.), right posterior sulcal plate (S.d.p.), median anterior sulcal plate (S.m.a.), and median posterior sulcal plate

(S.m.p.); (B) apical view of cell showing epithecal plates; (C) antapical view of cell showing hypothecal and some sulcal plates. Scale bar = 10 mm.

difficult to detect (Balech, 1995). Balech (1989, 1995)

located at least one of the two accessory plates and

therefore reported the formula of A. minutum as Po, 40,600, 6C, 5000, 20000 and 9–10S. These accessory plates were

possibly present, but were not located in the Jamaican

specimens, hence the formula Po, 40, 600, 6C, 5000, 20000 and

8S, which is the same as that put forward by Giacobbe

and Maimone (1994) who were also unable to detect

both accessory plates in specimens of A. minutum from

a Mediterranean lagoon.

The thecal plates of the Jamaican specimens were

typically divided into epithecal plates, hypothecal

plates, sulcal plates and cingular plates (Fig. 4A). As

the plate formula suggests, the epithecal plates

consisted of one apical pore plate (Po), four apical

plates (40) and six precingular plates (600) separated from

the hypothecal plates by six cingular plates (6C) lacking

much detail (Fig. 4A and B). The hypothecal plates

consisted of five postcingular plates (5000) and two

antapical plates (20000) (Fig. 4C). Eight visible sulcal

plates (8S) composed the sulcus located on the ventral

side of the cells (Fig. 4A).

3.2.2.1. The epithecal plates. The apical pore plate

(Po): the apical pore plate (Po) was approximately

4.8 mm long, teardrop shaped and located at the anterior

most point of the epitheca (Fig. 4A) where it was

surrounded by four apical plates (10–40) (Figs. 4B and

5A). This plate was convex on the left, concave to

straight on the right and tapered ventrally (Fig. 5C and

D). The dorsal margin of this plate varied from flattened

to slightly convex, while the ventral margin was

obliquely truncated in some cells and somewhat pointed

in others (Fig. 5C and D).

Each apical pore plate had a comma-shaped apical

pore or cavity called the foramen (f in Fig. 5C and D).

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–47 37

Fig. 5. Thecal plate morphology of Alexandrium minutum: (A) LM showing an apical pore plate (Po) surrounded by four apical plates, an indirect

connection between the first apical plate 10 and Po via a thread-like extension (arrowhead) and the position of the ventral pore (arrow); (B) LM of a

portion of the epitheca showing indirect connection between the 10 and Po (black arrow); (C) LM of Po showing position of the callus (c) and foramen

(f); (D) SEM showing structure of the Po including; the callus (c), foramen (f), canopy (d), marginal pores (m) and a direct connection (dc) between

the 10 and Po via a short anterior border; (Ea–d) LM showing variations in the morphology of the 10 and different positions of the ventral pore

(arrows). Scale bars = 5 mm.

Scanning electron microscopy revealed that in some

cells, the foramen was partially covered by a canopy as

indicated by (d) in Fig. 5D. On the ventral half of the

right margin of the foramen was a thickened area

forming a poorly developed callus which is known to

contribute to support of the canopy (c in Fig. 5C and D).

No anterior attachment pore was present and a number

of small marginal pores were observed surrounding the

foramen (m in Fig. 5D). Although the Po is rather

similar for most Alexandrium species, some have

characters that can be used to differentiate amongst the

species (Fukuyo, 1985). The Po of the Jamaican

specimens had the characters typical of A. minutum

described by Balech (1995), particularly the comma-

shaped foramen, poorly developed callus and absence

of an anterior attachment pore.

The apical plates: four apical plates surrounded the

apical pore plate (Figs. 4B and 5A). The first apical

plate (10) (Figs. 4B and 5A and B) has the most

taxonomic value because of its visible and distinguish-

ing characteristics (Balech, 1995) and therefore was

used as a taxonomic criterion in the identification of A.

minutum in this study.

The first apical plate (10) was rhomboidal however

variations in this shape were observed as shown in

Fig. 5Ea–d. The right posterior side of the plate was

straight to slightly concave, slanted up to the right

anterior side of the plate (Fig. 5Ea–d) and articulated

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–4738

with the sixth precingular plate (Figs. 4B and 5A and B).

The right anterior side of the 10 was in contact with the

fourth apical plate (40) (Figs. 4B and 5A and B) and was

slightly concave in some cases (Fig. 5Ea), straight in

others (Fig. 5Eb) and angular in a few cells (Fig. 5Ec).

All 10 had a small ventral pore which in most cells was

situated close to the posterior extreme of the anterior

right margin, on the suture between the first and fourth

apical plates as reported by Balech (1995) (black arrow

in Fig. 5A and black arrow in Fig. 5Ea). The presence of

the ventral pore is considered to be another important

taxonomic characteristic in the identification of A.

minutum (Balech, 1995). A small number of cells had

the ventral pore located close to the middle of the suture

as shown in Fig. 5Eb. A similar observation was made in

Vietnamese specimens of A. minutum (Yoshida et al.,

2000).

Fig. 6. Thecal plate morphology of Alexandrium minutum: (A) LM of sectio

(10) and the anterior sulcal plate (S.a.) and position and morphology of the six

sulcus; (Ca–f) LM showing variations in the morphology of the posterior s

The left posterior side of the 10 was in contact with

the first precingular plate (100) (Fig. 5B) and varied from

straight to gently convex (Fig. 5Ea and b). The left

anterior side varied from slightly concave to straight and

slanted up to the right (Fig. 5Ea–d). The posterior end of

the first apical plate was connected to the anterior sulcal

plate (S.a.) as shown in Fig. 6A and was usually

truncated in most cells (Fig. 5Ea), while a few cells had

a somewhat pointed or conical posterior end (Fig. 5Eb).

The most important characteristic of the first apical

plate is its position in relation to the Po: disconnected or

connected (Balech, 1995). All 10 of the Jamaican

specimens were observed to be connected to the Po

either indirectly or directly. The anterior end of the 10 inthe majority of cells was drawn out into a short to long

thread-like extension (Fig. 5Ea–c), which indirectly

connected the plate to the ventral margin of the apical

n of the epitheca showing the connection between the first apical plate

th precingular plate (600); (B) LM showing the eight visible plates of the

ulcal plate (S.p.). Scale bars = 10 mm.

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–47 39

pore plate as indicated by the black arrowhead in

Fig. 5A and black arrow in Fig. 5B. Some 10 lacked the

extension altogether (Fig. 5Ed) and were directly

connected to the apical pore plate by a very short

anterior border as indicated by the arrow (dc) in Fig. 5D.

Balech (1989) similarly reported both direct and more

often indirect connection between the Po and 10 of his A.

minutum specimens.

Characteristics of the remaining apical plates were of

little taxonomic value with the exception of the third

apical plate (30) for which symmetry or asymmetry has

some differential value (Balech, 1995). The 30 of the

Jamaican specimens was six sided and appeared to be

almost symmetrical as shown in Figs. 4B and 5A. These

characters were typical of the 30 of A. minutum cells

described by Balech (1989).

The precingular plates: surrounding the apical plates

and immediately above the cingulum were six

precingular plates known as the first, second, third,

fourth, fifth and sixth precingulars (100–600, respectively)

(Fig. 4A and B). The most characteristic and

taxonomically valuable of these plates is the sixth

precingular (600) (Fig. 6A) which can be used to some

extent to differentiate between Alexandrium species

(Balech, 1995). In the Jamaican specimens, the 600 was

small and narrow—longer than wide in comparison to

the other precingular plates, with a length/width ratio of

about 2:1, typical of A. minutum species, as described

by Balech (1989). The right posterior margin of the 600

was straight to slightly convex and articulated with the

500 (Fig. 6A). The right anterior margin was straight to

concave and articulated with the fourth apical plate

(Fig. 6A). The left posterior margin was arched or

slightly concave, to allow for attachment of the convex

right margin of the anterior sulcal plate (S.a.) (Fig. 6A),

while the left anterior margin was straight or slightly

convex to allow for articulation of the 10.

3.2.2.2. The sulcal plates. All sulcal plates have

taxonomic value (Balech, 1995). Each cell had a large

ventrally located sulcus which widened slightly poster-

iorly (Fig. 3F) and has been reported as being composed

of ten plates, eight of which were relatively visible

(Figs. 4A and 6B) in the Jamaican specimens and two

which are very small and were not observed during this

study.

The eight visible sulcal plates are shown in Fig. 6B

and were composed of one anterior sulcal plate (S.a.)

and one posterior sulcal plate (S.p.). Two lateral pairs

of plates were present with one pair being posterior

and composed of the left and right posterior sulcal

plates (S.s.p. and S.d.p.). The other pair was anterior

and composed of the left and right anterior sulcal

plates (S.s.a and S.d.a.). Two small median plates

known as the median posterior and anterior sulcal

plates (S.m.p. and S.m.a.) occurred between the two

anterior lateral sulcal plates, one above the other. Of

these sulcal plates the most distinctive characters are

found in the posterior and anterior sulcal plates

(Fukuyo, 1985).

The posterior sulcal plate (S.p.): the posterior sulcal

plate was somewhat variable in the length/width ratio,

usually being wider than long (Fig. 6Ca), however some

cells had a S.p. with a length approximately equal to the

width as shown in Fig. 6Cb. Most S.p. were somewhat

symmetrical with an irregularly thickened anterior

margin composed of gently concave right and left

regions, which met in the middle of the margin

(Fig. 6Ca). In some cells, the left region of the anterior

margin was almost straight (Fig. 6Cf) and the right

region of the margin in some cases extended down into

the plate creating a small indentation as shown in

Fig. 6Ca and b. Both the left and right sides of the S.p.

varied from straight to slanting to gently convex, with

the left side usually shorter than the right side

(Fig. 6Ca–f). The posterior margin was generally

convex, slanting down toward the left and then curving

up towards the anterior margin (Fig. 6Ca–f).

The observed variations in the morphology of the

S.p. are considered to be important characteristics in the

identification of A. minutum and were similar to

variations reported by Balech (1989), who particularly

noted variation in the length/width ratio and shape of the

anterior edge.

The surface of the S.p. was irregularly reticulated as

was typical of the hypothecal plates and this reticulation

varied in pattern from cell to cell (Fig. 6Ca–d and f).

Some S.p. had less reticulation and a stria running near

the periphery of the left, right and posterior margins as

shown in Fig. 6Ce. No attachment pore was present on

the S.p. as also reported by both Yuki (1994) and

Yoshida et al. (2000) for A. minutum cells from Japan

and Vietnam, respectively. The anterior margin of the

S.p. articulated with two smaller lateral sulcal plates

known as the right and left posterior sulcal plates (S.d.p.

and S.s.p.) (Figs. 6B and 7A).

The right posterior sulcal plate (S.d.p.): the right

posterior sulcal plate (S.d.p.) was longer than wide and

had a generally rectangular shape which varied from

cell to cell (Fig. 7Ba–e), but fit previous descriptions of

this plate by Balech (1989, 1995). The posterior margin

of the S.d.p. articulated with the right region of the

anterior margin of the posterior sulcal plate (Fig. 7A)

and varied from straight to irregularly convex but most

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–4740

Fig. 7. Thecal plate morphology of Alexandrium minutum: (A) LM of portion of the sulcus showing the posterior sulcal plate (S.p.), right posterior

sulcal plate (S.d.p.) and left posterior sulcal plate (S.s.p.); (Ba–e) LM showing variations in the morphology of the right posterior sulcal plate; (Ca–c)

LM showing variations in the morphology of the left posterior sulcal plate. Scale bars = 5 mm.

often was observed to slant to the left and anteriorly

(Fig. 7Ba–e). The anterior margin also varied from

straight as shown in Fig. 7Bc and d, to slanting gently

down towards the left (Fig. 7Ba and b). The external

margin of this plate was irregularly convex and often

interrupted by small grooves or indentations (Fig. 7Bd).

The internal margin varied from straight to gently

convex, also interrupted by grooves in some cells as

shown in Fig. 7Bd and e and sometimes with a small

indentation just before meeting the anterior margin

(Fig. 7Bd and e).

The left posterior sulcal plate (S.s.p.): the left

posterior sulcal plate (S.s.p.) had an asymmetrical

rectangular to square-like shape and was relatively short

with a width almost equal to the length in most cases,

however some plates were slightly longer than wide.

The posterior margin of this plate articulated with the

left region of the anterior margin of the S.p. (Fig. 7A)

and varied from straight or slightly convex to slanting to

the right and anteriorly (Fig. 7Ca–c). The external

margin of the S.s.p. was somewhat straight to slightly

convex, while the internal margin varied from straight to

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–47 41

Fig. 8. Thecal plate morphology of Alexandrium minutum: (A) LM showing the articulation of the right anterior sulcal plate (S.d.a.) with the right

posterior sulcal plate (S.d.p.); (Ba–b) LM showing variations in the morphology of the right anterior sulcal plate; (C) LM showing the articulation of

the left anterior sulcal plate (S.s.a.) with the left posterior sulcal plate (S.s.p.); (D) LM showing a variation in the morphology of the left anterior

sulcal plate. Scale bars = 5 mm.

slightly concave (Fig. 7Ca–c). The anterior margin of

the plate in most cells had a straight left side and a right

side, which curved down to the right as shown in

Fig. 7Ca and b. In a few cases the left side of the plate

was not straight, but curved down to the right as shown

in Fig. 7Cc. These slight variations in morphology

matched the descriptions and drawings of this plate by

Balech (1989, 1995).

The right anterior sulcal plate (S.d.a.): attached to

the anterior margin of the S.d.p. was another sulcal

plate known as the right anterior sulcal plate (S.d.a)

(Figs. 6B and 8A). This plate was triangular in shape,

which varied somewhat from cell to cell as shown in

Fig. 8Ba and b. The S.d.a. was usually longer than

wide, with a straight and horizontal posterior margin

(Fig. 8Ba and b). The right side of the plate was in

some cells slightly concave (Fig. 8Ba) while in others

it was deeply concave as shown in Fig. 8A and Bb.

The edge of the left anterior side was thickened and in

most cases strongly curved towards the right and

posteriorly (Fig. 8A and Bb). Like the left posterior

sulcal plate, variations in the morphology of this plate

were minor and fit descriptions presented by Balech

(1989, 1995).

The left anterior sulcal plate (S.s.a.): attached to the

left side of the anterior margin of the S.s.p. was the left

anterior sulcal plate (S.s.a.) (Fig. 8C). This plate was

longer than wide and somewhat rhomboidal in shape,

with a wide posterior region and narrow, pointed

anterior region (Fig. 8C and D). The posterior margin of

the S.s.a. had a relatively straight right side which

articulated with the left posterior sulcal plate (S.s.p.) as

shown in Fig. 8C and a left side (sometimes shorter or

longer than the right side) inclined up towards the left

(white arrowheads in Fig. 8C and D). The internal

margin of the plate was slightly concave and vertical in

some cells as shown in Fig. 8C, while in others this side

was inclined to the right (Fig. 8D). The external anterior

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–4742

Fig. 9. Thecal plate morphology of Alexandrium minutum: (A) LM showing the articulation of the median posterior sulcal plate (S.m.p.) with the left

posterior sulcal plate (S.s.p.); (B) LM showing the connection between the S.m.p. (arrowhead) and the left anterior sulcal plate (S.s.a.); (C) LM

showing the morphology of the S.m.p.; (D) LM showing the morphology of the median anterior sulcal plate (S.m.a.); (Ea–e) LM showing variations

in the morphology of the anterior sulcal plate and the position of the unciform apophysis (ua). Scale bars = 5 mm.

side was gently curved towards the right, ending in a

tapered, pointed anterior region (Fig. 8C and D).

Variation in the morphology of this sulcal plate was the

least when compared to that of the other sulcal plates,

however observations matched those of Balech (1995).

The median posterior and anterior sulcal plates

(S.m.p. and S.m.a.): between the left and right anterior

sulcal plates were two small, narrow median plates

known as the median posterior and median anterior

sulcal plates (S.m.p. and S.m.a., respectively) (Fig. 6B).

The S.m.p. was longer than wide and somewhat

pentagonal in shape (Fig. 9C). The posterior margin of

this plate was straight to slightly convex and inclined up

towards the left and articulated with the right anterior

margin of the S.s.p. (Fig. 9A). The external margin of

the S.m.p. was slightly concave and connected to the

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–47 43

Fig. 10. Thecal plate morphology of Alexandrium minutum: (A) LM showing the hypothecal plates; (Ba–d) LM showing variations in the

morphology of the first postcingular plate (1000); (Ca–d) LM showing variations in the morphology of the fifth postcingular plate (5000). Scale

bars = 5 mm.

left anterior sulcal plate (S.s.a.) (Fig. 9B). The internal

margin started straight and slanted up to the right,

followed by another straight side which was inclined to

the left as shown in Fig. 9C. The anterior margin of this

plate was also straight and horizontal, articulating with

the posterior margin of the median anterior sulcal plate

(Fig. 4A).

The median anterior sulcal plate (S.m.a.) like the

S.m.p, was narrow and elongated but smaller than the

S.m.p. (Fig. 9D). The posterior margin of the S.m.a. was

straight where the plate joined the S.m.p. The posterior

internal margin of the plate curved up to the right

forming a rounded anterior region as shown in Fig. 9D

which articulated with the unciform apophysis of the

anterior sulcal plate (Figs. 4A and 9Ed). The anterior

external margin of the plate was also straight and almost

vertical and followed by a slightly concave side that was

inclined up to the right (Fig. 9D).

Location and identification of these two median

plates was difficult as they were fairly small and hard to

locate in an intact sulcus. The morphology of these

plates does however fit that of previous descriptions

(Balech, 1995).

The anterior sulcal plate (S.a.): the morphology of

the eighth plate of the sulcus, the anterior sulcal plate

(S.a.) (Fig. 9Ea–e) is very important in the identification

of A. minutum and according to Balech the character-

istics of this plate have greater taxonomic value than

those of the posterior sulcal plate.

The anterior margin of the S.a. did not indent the

epitheca (Fig. 4A) and varied from straight to oblique to

slightly convex (Fig. 9Ea–e) and articulated with the

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–4744

Fig. 11. Thecal plate morphology of Alexandrium minutum: (Aa–f) LM showing variations in the morphology of the first antapical plate (10000). Scale

bars = 5 mm.

first apical plate (Fig. 6A) and the first antapical plate

(Fig. 4a). The posterior margin was interrupted by a

fairly round, deep posterior sinus, giving rise to two

posterior arms or branches. The left branch was narrow

with a posterior margin, which articulated with the left

anterior sulcal plate, and a left margin which varied

from straight to slanting, to slightly concave or convex

(Fig. 9Ea–e) and articulated with one of the plates of the

cingulum. The right branch also known as the unciform

apophysis (ua in Fig. 9Ed), was thinner than or equal to

the left branch in width, with a straight, slanting or

slightly convex margin (Fig. 9Ea–e). This unciform

apophysis articulated with the rounded anterior region

of the median anterior sulcal plate, which almost closed

the posterior sinus of the anterior sulcal plate.

The posterior and anterior accessory sulcal plates

(S.ac.p. and S.ac.a.): the posterior and anterior

accessory sulcal plates observed in previous studies

of A. minutum (Balech, 1989, 1995; Yuki, 1994) were

not observed during this study. This could suggest the

lack of these plates in the Jamaican specimens, however

their extremely small size of 1 mm long or shorter

(Balech, 1989), could have resulted in them being

overlooked, if present, and hence the presence or

absence of these two accessory plates in the Jamaican

specimens is inconclusive.

3.2.2.3. The hypothecal plates. The postcingular

plates: immediately below the cingulum were the five

postcingular plates of the hypotheca known as the first,

second, third, fourth and fifth precingular plates (1000–5000, respectively) (Fig. 4A and C). Of these five plates

the fourth postcingular (4000) was the largest, as well as

the largest of the hypothecal plates (Fig. 10A). The most

characteristic postcingular plates that aided with the

identification of the species were the first (1000) and fifth

(5000) postcingular plates (Figs. 4C and 10A and Ba–Cd)

which both matched the description of these plates

provided by Balech (1989, 1995).

The 1000 was short and somewhat elongated or wide,

with a relatively straight posterior margin slanted down

towards the left (Fig. 10Ba–d). The anterior margin

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–47 45

Fig. 12. Thecal plate morphology of Alexandrium minutum: (Aa–e) LM showing variations in the morphology of the second antapical plate (20000).Scale bars = 10 mm.

varied from gently convex to straight to slightly concave

in some cases (Fig. 10Ba–d). The external margin

varied from straight to slightly convex while the internal

margin slanted to the right, up towards the anterior

margin, giving rise to a pointed triangular region

(Fig. 10Ba–d). This internal margin was reinforced and

articulated with the left anterior sulcal plate (Fig. 4A).

The 5000 was higher than the first, similarly wide, with

reticulations which varied from strong to weak

(Fig. 10Ca–d). The posterior margin articulated with

the posterior sulcal plate (Fig. 4C) and was observed to

be short, inclined up to the left and varied from straight

to jagged (Fig. 10Ca–d). The external margin varied

from straight to convex and slanted up towards the right

as shown in Fig. 10Ca–d. The anterior margin of the

fifth postcingular was gently convex in most cells and

straight in some as shown in Fig. 10Cb. The internal

margin of this plate also showed variations from straight

to gently concave to jagged and somewhat angular

(Fig. 10Ca–d). This side was also reinforced where the

plate articulated with the right posterior sulcal plate.

The antapical plates: the final plates of the

hypotheca were the two plates known as the first and

second antapical plates (10000 and 20000, respectively)

(Figs. 4C and 10A). Of all the hypothecal plates the two

antapical plates provide the most valuable information

with regards to the identification of the A. minutum

species (Balech, 1995) and like the previous hypothecal

plates matched the descriptions of Balech (1989, 1995).

The first antapical 10000 was pentagonal with a

relatively straight to slightly convex posterior margin

(Fig. 11Aa–f). The left margin was generally angular,

slanting up to the left then back towards the right

(Fig. 11Aa–f). The right margin was reinforced where it

articulated with the posterior and left posterior sulcal

plate (Fig. 4C) and in most cases started out straight and

vertical then became gently concave towards the

anterior margin (Fig. 11Aa–d). In some cells the right

margin of the 10000 remained more or less straight

(Fig. 11Af) or inclined to the left approaching the

anterior margin (Fig. 11Ae). The anterior margin was

very short and straight (Fig. 11Aa–f) and articulated

with the left anterior sulcal plate (Fig. 4A). Reticulation

of the 10000 varied from strong (Fig. 11Aa–e) to very

weak as shown in Fig. 11Af.

The second antapical 20000 was somewhat pentagonal

and varied from being longer than wide to wider

than long, with strong reticulation in most cases

(Fig. 12Aa–e). The posterior margin was straight to

gently curved to the left (Fig. 12Aa–e) and connected to

the third postcingular 3000 (Fig. 4C). The right side was

convex and connected to the fourth postcingular 4000

(Fig. 4C) and varied from short to long (Fig. 12Aa–e).

The left side slanted up to the left, was gently convex,

E.R. Ranston et al. / Harmful Algae 6 (2007) 29–4746

connected to the second postcingular 2000 (Fig. 4C) and

also varied from short to long (Fig. 12Aa–e). The left

side of the anterior margin was straight, slanting to the

right and connected to the first antapical 10000 (Figs. 4C

and 12Aa–e). This side was followed by a concave right

side, which connected, to the posterior sulcal plate

(Figs. 4C and 12Aa–e).

4. Conclusion

The reported observations on the morphology and

specifically the plate patterns of the Jamaican speci-

mens of A. minutum were in good agreement with

classical descriptions of A. minutum presented by

Balech (1989, 1995) and do not present substantial

differences in plate tabulation and morphology.

A. minutum is characterized by its small size, the

rhomboidal first apical 10 which is directly or, more

often, indirectly connected to the comma shaped Po, a

ventral pore which is situated in the posterior half of the

right upper side of 10, the narrow S.a. as long as wide or

longer than wide, the short, wider than long S.p., the

narrow precingular 600 and the constant lack of anterior

and posterior attachment pores (Balech, 1995). These

are all characters, which are defined as typical of A.

minutum and are used to distinguish this species from

other species of Alexandrium, and were characters

possessed by the Jamaican specimens.

These specimens showed some slight variations from

the typical description of the species, however these are

not considered to be significant. A distinctly reticulated

hypotheca as seen in the Jamaican specimens is not

considered to be typical (Balech, 1995), but A. minutum

cells from Italy also had strong reticulations suggesting

high variability in the appearance of the hypothecal

surface possibly due to environmental conditions

(Balech, 1995). The ventral pore of the Jamaican

specimens was not always near the posterior margin of

the 10, but sometimes in the middle. Such a variation

was also described by Yoshida et al. (2000) for A.

minutum specimens from Vietnam.

To date nostudiesof the toxic potentialof the Jamaican

specimens of A. minutum have been conducted, however

all Alexandrium species should be regarded as potentially

toxic until proven otherwise. The fact that a massive fish

kill accompanied the bloom suggests the possibility that

the Jamaican specimens of A. minutum are toxic. The fish

kill may have been as a result of oxygen depletion during

the bloom, however the possibility exists that death could

have occurred due to close contact with, or direct

ingestion of paralytic shellfish toxin producing A.

minutum cells, or ingestion of zooplankton which had

fed on the cells (White, 1981). The relationships between

fish kills, paralytic shellfish toxins and the marine food

web have been reviewed by White (1984). Marine fish are

in general very sensitive to paralytic shellfish toxins

although some species can accumulate and retain the

toxins without being affected (Geraci et al., 1989).

With potentially toxic A. minutum being a consistent

and sometimes dominant member of the phytoplankton

community of Hunts Bay, and with concentrations far

exceeding the acceptable limits in other countries, the

continual use of this bay as a source of food is cause for

great concern. Fishermen of surrounding communities

fish for finfish, crabs, shrimp and shellfish in Hunts Bay

everyday, including during red tide occurrences. Bait fish

caught every morning in the bay are used to catch larger

fish outat sea, compounding the potential for toxic events.

There are no known cases of PSP in Jamaica, but the

potential for its occurrence is ever present as long as A.

minutum continues to occur and bloom in Hunts Bay

and possibly other Jamaican coastal waters that are used

as food sources by humans and other animals. PSP is

appearing in regions where it has never been known

(Kao, 1993) and Jamaica is certainly one of these

regions. With no historical data on this species and lack

of expertise on PSP events, such an occurrence could

have detrimental effects on commercial fisheries, public

health and the economies of local areas in the country.

Acknowledgements

We gratefully acknowledge the IOC-DANIDA

(Intergovernmental Oceanographic Commission, Dan-

ish Agency for International Development Aid) Science

and Communication Centre on Harmful Algae for

funding this study and providing literature and training

at workshops on the identification of harmful marine

microalgae at the University of Copenhagen. Thanks to

staff of the Botanical Institute, University of Copenha-

gen for their assistance with the electron microscope

observations and photography. Thanks also to The

Department of Life Sciences, University of the West

Indies, Mona Campus in Jamaica, for use of inverted

and compound microscopes and the Port Royal Marine

Laboratory in Jamaica for providing boat transport and

accommodation during the field work phase of both the

1994 and 2004 exercises.[SS]

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