Impact of disease on the survival of three commercially fished species

Abstract

Recent increases in emergent infectious diseases have raised concerns about the sustainability of some marine species. The complexity and expense of studying diseases in marine systems often dictate that conservation and management decisions are made without quantitative data on population-level impacts of disease. Mark-recapture is a powerful, underutilized, tool for calculating impacts of disease on population size and structure, even in the absence of etiological information. We applied logistic regression models to mark-recapture data to obtain estimates of disease-associated mortality rates in three commercially important marine species: snow crab (Chionoecetes opilio) in Newfoundland, Canada, that experience sporadic epizootics of bitter crab disease; striped bass (Morone saxatilis) in the Chesapeake Bay, USA, that experience chronic dermal and visceral mycobacteriosis; and American lobster (Homarus americanus) in the Southern New England stock, that experience chronic epizootic shell disease. All three diseases decreased survival of diseased hosts. Survival of diseased adult male crabs was 1% (0.003-0.022, 95% CI) that of uninfected crabs indicating nearly complete mortality of infected crabs in this life stage. Survival of moderately and severely diseased striped bass (which comprised 15% and 11% of the population, respectively) was 84% (70-100%, 95% CI), and 54% (42-68%, 95% CI) that of healthy striped bass. The disease-adjusted yearly natural mortality rate for striped bass was 0.29, nearly double the previously accepted value, which did not include disease. Survival of moderately and severely diseased lobsters was 30% (15-60%, 95% CI) that of healthy lobsters and survival of mildly diseased lobsters was 45% (27-75%, 95% CI) that of healthy lobsters. High disease mortality in ovigerous females may explain the poor recruitment and rapid declines observed in this population. Stock assessments should account for disease-related mortality when resource management options are evaluated.

Dermal mycobacteriosis and warming sea surface temperatures are associated with elevated mortality of striped bass in Chesapeake Bay

“…Marine diseases can have lasting effects on populations as well as their associated ecological communities (Aronson & Precht, ; Behrens & Lafferty, ; Groner et al., ; Hoenig et al., ). Management of high‐impact diseases requires quantification of their population‐level effects and identification of factors that facilitate transmission, mortality, and morbidity (Groner et al., ).…”

“…For example, it is possible to incorporate environmental and biotic covariates that may drive survival, disease progression, or encounter rates. While mark–recapture is commonly used to estimate population sizes and survival rates of numerous fished species (Pine, Pollock, Hightower, Kwak, & Rice, ), or epidemiological processes in terrestrial species (e.g., Graham et al., ), it is rarely used to estimate disease processes in marine species (Chaloupka, Balazs, & Work, ; Hoenig et al., ). Unlike terrestrial systems, recapture of tagged individuals in marine systems is frequently done by commercial or recreational fishermen, who may not be qualified to assess the disease state of a recaptured animal.…”

“…in fishes (Colorni, ), disease in striped bass develops slowly and some individuals appear to survive for long periods with low‐level infections (Jacobs, Rhodes, Sturgis, & Wood, ). Prevalence of dermal mycobacteriosis of fish caught in commercial pound nets can exceed 60% in the Rappahannock River, and recent models suggest that, for fish with severe signs of disease, survival can be 46% lower than in healthy animals (Hoenig et al., ). Disease‐associated mortality was previously observed in a study of visceral mycobacteriosis in striped bass from the Chesapeake Bay mainstem (Gauthier et al., ).…”

“…Disease‐associated mortality was previously observed in a study of visceral mycobacteriosis in striped bass from the Chesapeake Bay mainstem (Gauthier et al., ). Despite recognition of its potential to cause mortality, quantitative estimates of the population‐level effects of the disease are lacking (Gauthier et al., ; Hoenig et al., ; Vogelbein et al., ). Moreover, it is unknown whether variable capture rates across disease severity states may have biased previous estimates of disease prevalence from a Rappahannock River tag‐recapture study focused on dermal mycobacteriosis (Hoenig et al., ), and a Chesapeake Bay mainstem trawl survey focused on splenic mycobacteriosis (Gauthier et al., ).…”

Shell disease in Crangon crangon (Linnaeus, 1758): The interaction of temperature and stress response

“…Due to the altered expression of different genes and hormones crustaceans can be energetically compromised or produce elevated levels of ecdysone, pointing towards changes in the molting behavior (Castro et al, 2006;Laufer et al, 2005;Tarrant et al, 2012). Shell disease can also be lethal due to secondary invading pathogens into the epidermis and underlying tissues causing sepsis of the host or impairments of locomotion and feeding functions (Dyrynda, 1998;Hoenig et al, 2017;Smolowitz et al, 1992). In all ectothermic organisms such as C. crangon, temperature determines and interacts with embryogenesis, growth, molting frequencies and also the reproduction and survival (Caudri, 1939;Hufnagl and Temming, 2011a;Lloyd and Yonge, 1947;Siegel et al, 2008;Tiews, 1954).…”