Background: Zooplankton samples were collected fortnightly from four locations representing oceanic, shelf and harbour waters off Kingston, Jamaica in 2004, approximately 40 years after a similar study was concluded in 1964. The present sampling was conducted using vertical hauls with plankton nets of three different mesh sizes: 64, 200 and 600 μm between April and November 2004. ) at California Bank, an offshore bank. One hundred forty-seven different taxa of zooplankton were identified during this study. Eighty-one taxa were identified from Harbour Shoal Beacon (HSB), 106 from South-East Cay (SEC), 114 from the shelf-edge station, called Windward Edge (WE), and 94 from California Bank (CB). The pattern obtained from the clustering of stations using percent similarity coefficient (PSC) and Jaccard community coefficient (JCC) showed the presence of two distinct groups of stations: one with HSB and the other containing all other stations. The abundance of individual species was also examined for their potential to characterize the different water masses. As found 40 years ago, Lucifer faxoni and Penilia avirostris were indicators of eutrophic Kingston Harbour waters, while Microsetella norvegica and Farranula carinata were identified as indicators of offshore waters. Zooplankton parameters across the area clearly distinguished the eutrophic Kingston Harbour waters from the shelf and offshore sites but could not differentiate between the mesotrophic shelf and the offshore bank. Larval forms were numerically dominant across all stations with copepod nauplii, fish eggs and echinoderm larvae being major constituents. Conclusions: The zooplankton communities in the harbour, shelf and offshore areas of Jamaica's south-east coast still show significant spatial differences; however, the zooplankton community at the offshore bank was more similar to the shelf than was expected. Such banks although located offshore, receive enrichment due to associated circulation patterns. Therefore, they should not be considered oligotrophic and based on the zooplankton community distribution would be more accurately classified as mesotrophic.

Few studies have compared water quality and plankton along the eutrophication gradient from Kingston Harbour to oceanic waters around Jamaica. To compare the planktonic community along the expected nutrient gradient, we sampled every two weeks at four stations, from eutrophic Kingston Harbour to oceanic California Bank. Phytoplankton was assessed from whole water Niskin bottle casts and zooplankton by vertical hauls with plankton nets of three different mesh sizes: 64µm, 200µm, and 600µm. Total phytoplankton biomass declined sharply away from the harbour (1.0 μg L -1 at the Harbour Shoal Beacon to 0.2 μg L -1 at California Bank). Characteristic estuarine phytoplankton genera -such as Ceratium, Gonyaulax, Gyrodinium and Rhizosolenia-dominated harbour samples while genera characteristic of offshore locations -such as Asterionelliopsis, Navicula, Nitzschia, Rhizosolenia and Thalassionema-dominated California Bank. Highest phytoplankton densities (mean values of 34 174 cells L -1 ) were found at the harbor mouth. Mean zooplankton abundances ranged from maximum (5 858.5m -3 ) at Beacon to minimum (2 124.2 m -3 ) at California; 171 species of zooplankton were identified and copepods dominated with 76 species. Overall, 75 species of zooplankton were identified from Beacon, 107 from Port Royal Cays-South East Cay, 110 from the exposed shelf edgeWindward Edge, and 95 from the oceanic California Bank. Larval forms dominated; copepod nauplii, fish eggs and echinoderm larvae occurred at all sites. Lucifer faxoni and Penilia avirostris were indicative of harbor waters and Microsetella sp. and Farranula carinata of offshore waters. Some zooplankton taxa, like L. faxoni, Paracalanus parvus and copepod nauplii, despite showing gradual decline with distance from Beacon to the Edge, increased in abundance at the furthest station, California. California Bank clearly experiences enrichment which at times can be as high as near-shore areas, but the planktonic community is unique and similar only to those at other offshore station. To be reliable, characterization of water masses must involve a range of physicochemical and biological parameters. Rev. Biol. Trop. 62 (Suppl. 3): 259-272. Epub 2014 September 01.