Argus Fishery Research Articles

Ciguatoxin in Hawai'i: Fisheries forecasting using geospatial and environmental analyses for the invasive Cephalopholis argus (Epinephelidae)

Invasive species can precede far-reaching environmental and economic consequences. In the Hawai'ian Archipelago Cephalopholis argus (family Serranidae) is an established invasive species, now recognized as the dominant local reef predator, negatively impacting the native ecosystem and local fishery. In this region, no official C. argus fishery exists, due to its association with Ciguatera seafood poisoning (CP); a severe intoxication in humans occurring after eating (primarily) fish contaminated with ciguatoxins (CTXs). Pre-harvest prediction of CP is currently not possible; partly due to the ubiquitous nature of the microalgae producing CTXs and the diverse bioaccumulation pathways of the toxins. This study investigated the perceived risk of CP in two geographically discrete regions (Leeward and Windward) around the main island of Hawai'i, guided by local fishers. C. argus was collected and investigated for CTXs using the U.S. Food and Drug Administration (FDA) CTX testing protocol (in vitro neuroblastoma N2a-assay and LC-MS/MS). Overall, 76% of fish (87/113) exceeded the FDA guidance value for CTX1B (0.01 ng g−1 tissue equivalents); determined by the N2a-assay. Maximum CTX levels were ≅2× higher at the Leeward vs Windward location and, respectively, 95% (64/67) and 54% (25/46) of fish were positive for CTX-like activity. Fisher persons and environmental understandings, regarding the existence of a geographic predictor (Leeward vs Windward) for harvest, were found to be (mostly) accurate as CTXs were detected in both locations and the local designation of C. argus as a risk for CP was confirmed. This study provides additional evidence that supports the previous conclusions that this species is a severe CP risk in the coastal food web of Hawai'i, and that ocean exposure (wave power) may be a prominent factor influencing the CTX content in fish within a hyperendemic region for CP.

Ecophysiological biomarkers defining the thermal biology of the Caribbean lobster Panulirus argus

Tropical populations of marine species are predicted to be the most impacted by global warming because they are likely adapted to a narrow range of temperatures in their local environment. In the present study, we investigated the thermal range at which activity metabolic rate (AMR) is maximal, pejus, and critical in the spiny lobster Panulirus argus using different ecophysiological biomarkers. Lobsters were acclimated at constant temperatures (18, 22, 26 and 30°C; N=150) at laboratory conditions for 35days; after that time thermal biology was evaluated. Results obtained demonstrated that, in P. argus the temperature where AMR was maximal does not coincide with temperature that promotes the maximum growth rate (26°C). In fact, the preferred temperature, determined in a horizontal gradient was around the mean value of 27.5°C, 5.5°C above the temperature where animals showed their maximum metabolic scope, growth and thermal preference. Lactate and redox imbalance showed its maximum values in animals acclimated at 30°C indicating that lobsters where in pejus thermal ranges. Although lobsters are adapted to tolerate temperatures beyond 28°C, results indicated that temperature and exposure time play important roles in the way organisms respond to thermal challenges. It is likely that the difference in the responses of different ectothermic organisms and the thermal response is linked to the way these effects are measured. These results can help generate predictive models to anticipate changes in the P. argus fishery derived from likely changes in distribution and abundance of this species under warming scenarios of tropical oceans.

Lobster Houses as a Sustainable Fishing Alternative

The Caribbean Spiny Lobster (Panulirus argus) is overfished, primarily due to failures in fishery management. The most popular lobster fishing methods used are contributing to overfishing and are harmful to lobsters, the environment, and the health of the fishers. However, one method, lobster houses, shows particular promise for reducing these negative effects, but only if certain conditions are met. Lobster houses have been used for over fifty years by fishing communities in Ascension Bay, Mexico; and Batabano Bay, Cuba; which are two of the more successful P. argus fisheries in the Caribbean. Success in these two communities has led to the creation of lobster house projects throughout the region with varying levels of success. The objective of this study is to determine which factors contribute to the sustainability of the P. argus fishery by examining three lobster house case studies (Ascension Bay, Mexico; Batabano Bay, Cuba; and Miches, Dominican Republic) and the scientific literature that evaluates the sustainability of this fishery. Lobster houses can play a vital role in promoting sustainability throughout the Caribbean by simplifying management, reducing incidental

Panulirus argus virus 1 (PaV1) infection prevalence and risk factors in a Mexican lobster fishery employing casitas

In Bahía de la Ascensión in Mexico, the Caribbean spiny lobster Panulirus argus fishery is based on extensive use of artificial shelters (casitas) that can harbor both juveniles and adults of this highly gregarious species. There is concern that the use of casitas might increase contact transmission of Panulirus argus virus 1 (PaV1). However, a previous study found no evidence for lobster crowding within casitas influencing the prevalence of clinical PaV1 disease, although differences in clinical prevalence were noted between different bay environments. To investigate this more closely, 683 lobsters were sampled from casitas in 2 zones in this bay (Vigía Chico, a shallow low-vegetation zone, and Punta Allen, a deeper dense-vegetation zone) previously found to have the lowest and highest prevalence, respectively, of observed clinical signs. When hemolymph collected from these lobsters was tested by PCR, the prevalence of PaV1 infection was found to be significantly lower in Vigía Chico relative to Punta Allen irrespective of season or the size, sex, or presence of shell injuries on lobsters. Among 714 large commercial-catch lobsters collected throughout the bay, the prevalence of infection was low irrespective of year or sex. For all lobsters tested, the sensitivity (0.510) at which PaV1 infection was detected by observed clinical signs was about half that determined by PCR, but the specificity of clinical signs was absolute (1), indicating that a simple 2× correction factor can be used to accurately estimate PaV1 infection prevalence based on more easily conducted visual assessments of lobsters.

Size and reproductive status of fished spotted spiny lobster,Panulirus guttatus, in Morrocoy National Park, Venezuela: a preliminary report

The Venezuelan lobster-management plan is based on information collected from the Panulirus argus fishery in Los Roques Archipelago National Park. Panulirus guttatus are harvested illegally, as this species does not reach the minimum landing size (120 mm carapace length; CL). Fishers consider enforcement of a 120 mm minimum CL unjust and request a new regulation. The purpose of this study was to determine the basic population characteristics of P. guttatus at the Morrocoy National Park, to provide information for managers, and to establish a population monitoring program. Interviews with fishers were conducted from September to December 1999, and their catch was counted, measured, and sexed. Of the 163 lobsters surveyed, 93.3% wereP. guttatus, 6.1% P. argus, and 0.6% P. laevicauda. The size range for P. guttatus was 42.1 to 75.6 mm CL (average: 60.9 6.9 mm CL). Sex ratio favoured males (1.45:1), and 48.4% of the 62 females examined bore eggs. The smallest reproductive female measured 42.1 mm CL; the largest measured 67.7 mm CL. Fishing is carried out in shallow waters of the outer reefs; lobsters are harvested by hand during nocturnal skin diving.

Fisheries ecology of spiny lobsters Panulirus argus (Latreille) and Panulirus guttatus (Latreille) on the Bermuda Platform: estimates of sustainable yields and observations on trends in abundance

The maximum sustainable yield (MSY) of legal-size spiny lobsters Panulirus argus (Latreille) was estimated at 37 (±SE 7.7) × 10 3 animals by regression of catch per unit effort (CPUE) on total effort. A graphical plot of P. argus fishery catch and effort data for lobster seasons from 1975/76 to 1986/87 resulted in a second estimate of the P. argus MSY of 30 × 10 3 lobsters per season by a quadratic regression of catch on total effort. A graphical plot of catch on total fishing effort data for the Guinea chick Lobster Panulirus guttatus (Latreille), with a quadratic curve fit ( R 2 = 0.612), resulted in an estimate of MSY of approximately 33 × 10 3 lobsters per calendar year. The 1985 and 1986 fishery catches of Guinea chick lobsters were close to the MSY. There was an overall increase in the CPUE of P. argus lobsters (1975/76–1986/87), whereas there was an overall decline in the CPUE of P. guttatus spiny lobsters over the same time period. The two species interannual patterns of change of CPUE followed that of sea temperature change on the Bermuda Platform; superimposed was a 5-year cycle of CPUE, which was particularly noticeable with P. guttatus lobsters, suggesting a causal relationship with a 5-year cycle in the annual mean temperature of sea surface waters, averaged from six temperature stations on the Platform. Annual yield of P. argus lobsters was correlated with Platform average sea temperature at the 10% level (Spearman rank test). Both P. guttatus and P. argus yields on Platform sea temperature were parabolic in form. Platform CPUE of Guinea chicks on Hamilton Harbour temperature also suggested a parabolic relationship in the range 22–26 °C (coefficient of determination R 2 = 0.43). There was clearly a parabolic association between P. argus CPUE and Hamilton Harbour temperature over the same temperature range ( R 2 = 0.93). It is suggested that the Lellis and Russell quadratic model for survival and growth of P. argus postlarvae may be extended to juvenile P. argus to explain these findings.