No abstract

To forecast marine disease outbreaks as oceans warm requires new environmental surveillance tools. We describe an iterative process for developing these tools that combines research, development and deployment for suitable systems. The first step is to identify candidate host–pathogen systems. The 24 candidate systems we identified include sponges, corals, oysters, crustaceans, sea stars, fishes and sea grasses (among others). To illustrate the other steps, we present a case study of epizootic shell disease (ESD) in the American lobster. Increasing prevalence of ESD is a contributing factor to lobster fishery collapse in southern New England (SNE), raising concerns that disease prevalence will increase in the northern Gulf of Maine under climate change. The lowest maximum bottom temperature associated with ESD prevalence in SNE is 12°C. Our seasonal outlook for 2015 and long-term projections show bottom temperatures greater than or equal to 12°C may occur in this and coming years in the coastal bays of Maine. The tools presented will allow managers to target efforts to monitor the effects of ESD on fishery sustainability and will be iteratively refined. The approach and case example highlight that temperature-based surveillance tools can inform research, monitoring and management of emerging and continuing marine disease threats.

We present results of an international collaboration to survey American lobster Homarus americanus Milne-Edwards, 1837 nurseries in Atlantic Canada and the northeast United States from 2007 to 2009 under a standardized protocol involving two sampling methods, diver-based suction sampling and passive collectors. We surveyed young-of-year and older juveniles at 191 sampling sites over 39 sampling areas considerably expanding the known depth range and geographic limits of benthic recruitment. Young-of-year densities were strongly correlated in space with the abundance of older juveniles, signifying consistently strong settlement in the Gulf of Maine, lower Bay of Fundy, southwestern Nova Scotia and southern Gulf of St. Lawrence, and relatively weak settlement in southern New England, eastern coastal Nova Scotia and Newfoundland, a pattern consistent with commercial lobster harvests. Passive collectors elucidated bathymetric patterns of young-of-year recruitment in oceanographically contrasting regions. Although we observed young-of-year lobsters as deep as 80 m, they were most abundant above the thermocline in summer-stratified regions, such as the western Gulf of Maine and southern New England, and depth-wise differences were less extreme in thermally mixed waters of the eastern Gulf of MaineÁFundy region, a finding consistent with previous observations that postlarvae concentrate above the thermocline. Between the two samplers, we detected no sampling bias for young-of-year lobsters, although collectors may slightly underrepresent older juveniles entering from the surrounding sea bed. Finally, we found that interactions between juvenile lobsters and suspected predators or competitors in collectors, such as crabs and fishes, are weak and unlikely to bias collector results.

No abstract

Fishery‐independent trawl surveys are commonly used to monitor the status and trends of marine finfish species. Although bottom trawls are powerful sampling tools, they are limited to surveying relatively featureless bottom habitats and, as a result, may not accurately represent the trends in the relative abundance of fish species associated with structured and complex habitats. We evaluated the feasibility of rod and reel as an alternative fishery‐independent survey methodology to monitor the abundance of Tautog Tautoga onitis, a recreationally and commercially important structure‐dwelling reef fish, in the coastal waters of Massachusetts. Results suggest that a rod‐and‐reel survey is an effective, low‐cost approach to monitor the structured habitats inaccessible to trawl gears. Using a generalized linear mixed modeling framework we were able to identify important predictor variables influencing catch rates; variables that would be important in the design of a continued long‐term monitoring program and in the standardization of these data as an index of relative abundance. Variables retained in the top model included year, month, depth strata, bottom water temperature, tidal phase, fishing vessel, angler avidity, and random effects that accounted for the repeated measures survey design. Power analyses revealed that the directed rod‐and‐reel survey had far greater power to detect changes in Tautog abundance than the extant trawl survey, which had very little power to detect even large shifts in abundance. The results of this pilot study suggest that the continued use of rod and reel as a complementary survey tool would be warranted to further compare the trends in Tautog abundance generated using the two different survey methodologies, to reduce uncertainty in the stock assessment, and to improve the information upon which Tautog management is predicated in Massachusetts waters.