Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Public environmental awareness and support for management measures are key determinants of the scope for successful implementation of natural resource management. To assess user perceptions and opinions on resource state and potential management options for the coastal zone of Curaçao, we queried 250 coastal resource users from around the island (sport divers, part-time artisanal fishermen and recreational boaters) using ques­tionnaires. There is wide awareness of a long-term decline in coastal resource condition as measured by various indicators. Even among fishermen there was wide awareness of anthropogenic contributors to the decline, broad agreement of management measures required and a general willingness to contribute to management by means of annual license fees. Some of the more salient findings include the endorsement by fishermen of the current ban on spearfishing (81%), the regulation of the beach seine fishery for scad (77%), the introduction of fish reserves (72%), special protection for sea turtles (90%), conch (82%), and lobsters (72%), and notable support for grad­ual elimination of trap fisheries (45%). Also, both divers (65%) and boaters (92%) expressed the importance to them of an attractive coastline, with both groups expressing preference for natural (un-built) coastline (>74%) above other categories. Management based on the concept "user pays", as already implemented in the Nether­ lands Antilles on Saba and Bonaire, is well supported by the resource user public. A review of other main con­straints such as finances and institutional capacity, shows that conditions are quite favorable for implementation of new legislation. Modern coral reef management is urgently needed in Curaçao to safeguard a key natural resource and concerted action is called for on the part of government agencies, legislators and elected officials.

Orinoco River influence in the Caribbean Sea, characterized by high nutrient input, causes a decrease of Trichodesmium populations. The Caribbean Time Series (CaTS) station, south of Puerto Rico (17°36'N 67°00'W), was mon­itored for 25 months in order to observe the Trichodesmium abundance pattern and the presence of the river plume. In gen­eral, mean Trichodesmium abundance was higher at the surface and decreased with depth; The mean upper Waler column (surface to 20 m) abundance was 54.1t32.6 col/m3. Within the sampling period, abundance was highly variable (1-700 col/m3). Correlation between Trichodesmium abundance and wind speed (p=0.002), chlorophyll a concentration (p=0.001), nitrate (p=0.02) and silicate (p=0. 003)concentrations were statistically significant. However, Trichodesmium abundance was not correlated with salinity (p=0.70), temperature (p=0.16) and seawater density (p=0.71) variatious at CaTS. Eastern Caribbean regions highly influenced by the Orinoco River discharge were devoid of Trichodesmium colonies.

The associated fauna of Gracilariopsis tenuifrons (Gracilariaceae, Rhodophyta) cultures was collected between October 1994 and December 1996 in Chaeopata (Sucre State, Venezuela) and preserved in 10% formaldehyde. The species list includes 17 Crustacea, 14 Mollusca and six Polychaeta, the remaining taxa added ten species (total 47 species in eight Phyla). Grazing by mesoherbivores affected the algae and the mollusk Aplysia protea damaged new cultures significantly. The abundance of tubes built by the amphipod Eurirthonius brasiliensis impairs algal aspect and facilitates colonization by other organisms.

We analyzed growth; mortality and exploitation rate of Priacanhus arenatus, captured by the shrimp trawling fishery (1989-1996), in northeastern Venezuela. The growth coefficient (K) and the asymptotic length (L8) were estimated by length-frequency data using the Battacharya method and other routines of the FISAT pro­gram. Total mortality (Z) and exploitation (E) rates were obtained by length-converted catch curve analysis, based on length frequency data, and the Berveton and Holt's yield per recruit model, respectively. The mean growth parameters L and K were estimated as 474.7 mm and 0.69 year-1, respectively. Mean total mortality was 4.03 and the exploitation rate range was 0.70-0.80. Results indicated that the population is overexploited.

The use of Artemia salina nauplii as live food has significantly aided culture of commercial fish and shrimps in recent years. However, reported defficiencies in the nutritional value of some strains originated the study of freshwater fairy shrimps as an alternative to Artemia. This study presents cyst biometry for Dendro­cephalus geayi and D. spartaenovae (Anostraca: Thamnocephalidae), and the effects of some physicochemical variables on cyst hatching. The biometric characteristics of D. geayi and D. spartanovae are within the size range of commercial Artemia strains. Favorable conditions to batch D. geayi are 30°C and conductivity near that of distilled water (<5 μmhos). For D. spartaenovae, these conditions are 28 °C and 280 μmhos. A very low salinity such as 1% inhibits hatching in both species.

The sea urchin roe is among the highest valued seafood items in the world. Increasing demand has extended this fishery worldwide and cases of overfishing have been detected in some countries. On the eastern coast of Venezuela some species of sea urchin, such as Lytechinus variegatus, are consumed as food but studies to determine the abundance and size do no exist. Between February 1998 and April 1999 six sampling stations (depth under 5 m) in Cubagua island (perimeter 25 km) were visited in 11 occasions to study the population den­sity of L. variegatus, with a 0.25 m2 quadrat thrown eight times over seagrass (Thalassia testudinum) beds. Tem­perature was determined on site, and water samples for salinity and dissolved oxygen concentration were col­lected. Each specimen was measured and returned to the sea. Diameter range was 8.6 to 74.2 mm (n=3 404) and mean size 26.56-55.34 mm. On the northern coast density varied from 2 to 23 urchins 1m2; on the eastern coast from 15 to 82 /m2 and from 21 to 58 /m2 on the southern coast. On the north coast the seagrass beds are scarce.

The potential nutritional value of seven microalgal diets as measured by their ingestibility and digestibility to queen conch Strombus gigas larvae was tested with 30 day old larvae reared at 28°C and fed at 1000 cells ml-1. The algae were Tetraselmis suecica, Tetraselmis chuii, Isochrysis aff. galbana, Dunaliella ter­tiolecta, Chlamydomonas coccoides, Chaetoceros sp. and Thalassiosira fluviatilis. Ingestion and digestion were measured by the four nutritional stages studied with epifluorescence microscopy with live larvae. Temporal and absolute indices showed that arvae fed Chaetoceros sp. and T. fluviatilis had lower ingestion and digestion levels. The other algae are recommend to feed S. gigas larvae.

Melongena corona bispinosa was studied in Yucatán, México (21°16' N, 89° 49' W) for a year. Males have reproductive peaks in February and December, and a post-copulation peak in June. Female peaks are in March and May, plus oviposition peaks in April and January. Males and females differ in the mean gonadosomic index (F= 13.79, p<0.05) but not in the dry tissue/shell weight (F= 0.0902, p<0.05), dry tissue and total weight (F= 0.2466, p<0.05) and dry tissue weighl/internal shell volume (F= 1.0565, p<0.05).

The coral reef fish community was studied in Playa Mero, Morrocoy National Park, after the mass mortality of January, 1996 with a systematic sampling design. Transects and quadrates were used for corals, and a visual census for fishes. The coral community is highly disturbed with extensive areas of dead coral covered by algae, and low coverage and richness of coral species, gorgonians, sponges and briozooans. These factors have generated a relatively homogenius environment with respect to the fish community, which was dominated by Scaridae and Pomacentridae that represented 75% of fish. Dominant fishes were mainly herbivorous all fish) apparently because of the disturbance that caused the settling of algae.