Post-mortem examination of the Caribbean spiny lobster (Panulirus argus, Latreille 1804) and pathology in a fishery of the Lesser Antilles

A cryptic species of the nemertean egg predator Carcinonemertes conanobrieni (Simpson et al., 2017) detected using a barcoding approach infects the Caribbean spiny lobster Panulirus argus (Latreille, 1804) in the southwestern Caribbean Sea

A recently discovered nemertean egg predator, Carcinonemertes conanobrieni, inhabiting Panulirus argus egg masses poses a potential threat to this ecologically and commercially relevant lobster. This study assessed the prevalence of C. conanobrieni in the southwestern Caribbean Sea; Costa Rica and Panama. Brooding females of P. argus were collected by fishermen near Punta Uva beach, Costa Rica (n = 17), and Guna Yala, Panama (n = 19) and examined for the presence of C. conanobrieni. Prevalence of C. conanobrieni in brooding lobsters, determined as the presence/absence of adults, juveniles, encysted juvenile worms, or carcinonemertid egg masses was 47.06% and 31.58% in Costa Rica and Panama, respectively. Moreover, when indirect evidence (empty capsules and/or dead embryos presumably attacked/consumed by worms) of the presence of C. conanobrieni in brooding lobsters is considered in addition to direct evidence, prevalence of C. conanobrieni in brooding lobsters was 64.71% and 47.37% in Costa Rica and Panama, respectively. The observations suggest that this parasitic worm completes its life cycle locally in the southwestern Caribbean. Notably, a Maximum Likelihood phylogenetic analysis based on a fragment of the mitochondrial cox1 gene clustered two specimens collected in Costa Rica together with four other specimens previously collected in Saint Kitts into a single fully supported monophyletic clade that segregated from a second clade containing six specimens of C. conanobrieni collected in Colombia, Florida, and Saint Kitts. The barcoding analysis suggests that there is an undescribed species of Carcinonemertes, anatomically like C. conanobrieni, infecting P. argus in Costa Rica.

Vibrio harveyi in a Caribbean spiny lobster (Panulirus argus) with hepatopancreas necrosis

A Caribbean spiny lobster, Panulirus argus, was submitted for necropsy after a number of species-specific fatalities in a public aquarium. The hemolymph was opaque and did not clot and the hepatopancreas had multiple foci of necrosis centered on gram-negative bacteria. Pure cultures of Vibrio harveyi were isolated, identified initially by matrix laser desorption ionization-time of flight mass spectrometry, and confirmed by multilocus sequencing of the gyrB, recA, rpoA, and pyrH genes. As Caribbean spiny lobsters continue to be used for consumption and displayed in public aquariums, chronicling potential pathogens is warranted to inform differential diagnoses and to develop management strategies to reduce incidence of infectious disease in captive populations.

The effect of the egg-predator Carcinonemertes conanobrieni on the reproductive performance of the Caribbean spiny lobster Panulirus argus

BACKGROUND

The Caribbean spiny lobster Panulirus argus is heavily fished throughout its Greater Caribbean and Gulf of Mexico distribution, suggesting a heightened susceptibility to a fisheries collapse. In 2017, a nemertean worm, Carcinonemertes conanobrieni was described from ovigerous females of P. argus in Florida, USA. A year later, the presence of the same egg predator was recorded along the southern Caribbean coast (Colombia). The effect of this egg predator on the reproductive performance, including fecundity, embryo mortality, and reproductive output, of its host is unknown. This study tested whether C. conanobrieni affects embryo mortality, fecundity, and reproductive output in brooding females of P. argus.

RESULTS

Artisan fishers caught 90 ovigerous lobsters near Pueblo Viejo, Magdalena, Colombia. Each ovigerous female was examined for the presence/absence of the egg predator. Lobster egg mortality (%), fecundity (nº eggs female-1), and reproductive output (%) were estimated. Prevalence of C. conanobrieni in the studied population was 87.78%. The mean intensity of C. conanobrieni (all life stages) in the population was 11.68 (± 1.98) egg predators per brood mass sample. Infected females brooding late-stage embryos exhibited lower fecundity, lower reproductive performance values, and higher embryo mortality compared to infected females brooding early-stage embryos. Embryo stage and worm infection level negatively impacted fecundity and reproductive output. Worm infection level and the number of adult nemertean worms also negatively affected embryo mortality.

CONCLUSIONS

These results demonstrate an adverse effect of C. conanobrieni on the reproductive performance of P. argus. The interactive impact of this egg predator, natural stressors, and anthropogenic stressors on individual P. argus reproductive performance could facilitate losses at large-scale fisheries levels.