Cooperative Research to Evaluate an Incidental Catch Distribution Forecast

Abstract

Concern over incidental catches in commercial fisheries has been increasing, and while simple mitigation strategies have been effective, few effective mitigation strategies have been established for more complex species interactions. Incidental catches of alewife (Alosa pseudoharengus) and blueback herring (A. aestivalis) in the commercial Atlantic herring (Clupea harengus) fishery have received substantial attention on the Northeast U.S. continental shelf, despite an existing bycatch avoidance program. This study evaluates the utility of existing species distribution forecasts to predict river herring catches in the southern New England small mesh bottom trawl Atlantic herring fishery, with the ultimate goal of incorporating incidental catch forecasts into the bycatch avoidance program. Commercial Atlantic herring bottom trawl vessels assisted with field-based evaluation of alewife, blueback herring, and Atlantic herring species distribution forecast models. Vessels were equipped with conductivity, temperature, and depth probes, and sampling occurred throughout the fishery season (January-March). Locations of expected low and high forecasted incidental catches were sampled, as well as locations the captain expected to find low and high incidental catches. This allowed us to sample within the spatial area the fishery occurs, and to evaluate the forecasted conditions, and predictions, at the spatial scale of the fishery. Catch differences between high and low probability stations were small and variable, as were differences in modeled probability of species presence. No differences were observed between observations at model-predicted stations and captain-selected stations. The sampling provided a better understanding of the potential effectiveness of distribution forecasts for further reducing incidental catches. Existing models have limited use at the spatial scale of this fishery, but could be improved by developing models with fishery-dependent data. Collaborations between researchers, managers, and the Atlantic herring commercial fleet have improved relationships between the groups, and continued collaboration in the development and evaluation of incidental catch reduction tools is key for further reducing incidental catches.

Alewife and Blueback Herring Captured by Intertidal Weirs of the Inner Bay of Fundy, Canada, Display Seasonal Demographics that Suggest Multiple Migrating Stocks

“…Another BoF river herring population with a substantial Blueback Herring component is in the Saint John River, New Brunswick (Messieh 1977; Jessop 1990), and they could be entering Minas Basin from there. Limited knowledge of the spatial and temporal migration patterns of both species in mixed schools makes it difficult to develop prediction models for river herring in ocean habitats (Bethoney et al 2013; Turner et al 2017).…”

“…Much of the published research on river herring has been from studies in coastal rivers and estuaries, and some information is available on local movements of adults and juveniles (e.g., Eakin 2017). However, little is known about their biology and ocean migration patterns in Canada and the United States after they leave freshwater habitats (Neves 1981;Stone and Jessop 1992;Bethoney et al 2014;Turner et al 2016Turner et al , 2017. Ocean tagging studies have, to our knowledge, proven largely unsuccessful.…”

“…Ocean tagging studies have, to our knowledge, proven largely unsuccessful. In addition, there is a general lack of understanding about where and how these two species utilize habitats during the ocean migratory phase, although recent studies modeling ocean climate change and habitat associations may increase this knowledge (Lynch et al 2015;Turner et al 2016Turner et al , 2017.…”

Practical considerations for operationalizing dynamic management tools

“…Regular meetings also help build and maintain working relationships between parties, creating communication lines for discussing future tool developments, troubleshooting issues, or ground‐truthing management recommendations (see an example of a ground‐truthing programme in Turner et al. ). Additionally, bottom‐up stakeholder‐driven approaches (such as the DM tools described in O'Keefe & DeCelles and Eveson et al.…”

A Review of River Herring Science in Support of Species Conservation and Ecosystem Restoration

“…Subsequent testing of the models revealed some marginal ability to predict areas of higher incidental catch (Turner et al. 2017a, 2017b). Efforts are currently underway to combine the two approaches.…”