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Discard mortality studies are considered a primary research priority, particularly for species and fisheries where discard rates are high. Monkfish (the commercial name for Goosefish) Lophius americanussupports the most lucrative finfish fishery in New England, and it is also the second highest bycatch species by weight in the sea scallop dredge fishery. Despite its commercial importance, no data exist with respect to monkfish discard mortality estimates for any gear type. The goals of this study were to evaluate the discard mortality process for monkfish captured in sea scallop dredge gear, estimate mortality rate, and develop best handling/management practices to mitigate the impact of monkfish bycatch in the sea scallop dredge fishery. Discard mortality was estimated during a field study conducted between June and October 2017 on board sea scallop commercial fishing vessels on Georges Bank in the Northwest Atlantic. Pop‐up satellite tags were affixed to 60 monkfish to track survival from 14 to 28 d postcapture. From these monitored individuals, high predation rates were observed (n= 18 out of 26 mortalities), and the bulk of mortalities (n= 21) occurred within the first 24 h of discarding. However, in light of having no clear method for disentangling capture‐related and tag‐induced predation, predation was noted exclusively as one or the other to account for uncertainty and provide an upper and lower bound of mortality. This approach suggested that the discard mortality rate was between 17.9% and 54.1% for monkfish discarded by scallop dredges and that elevated air temperatures (above thermal preferences) may contribute to increased mortality. Based on these results, it appears that monkfish discard mortality is lower than previous assumptions of 100%, and potential best‐practice management suggestions moving forward may include minimizing fishing in areas of high monkfish abundance or scheduling rotating time/area closures during periods when air temperature exceeds monkfish thermal tolerance of 13°C.

Empirical discard mortality rate estimates are vital to both stock assessments and fishery management, especially for stocks that experience high discard rates, such as in the recreational rod‐and‐reel fishery for Haddock Melanogrammus aeglefinusin the Gulf of Maine. The objective of the present study was to derive a fishery‐scale discard mortality rate estimate for Haddock that are captured and released in the Gulf of Maine recreational fishery by combining results of an electronic‐tagging telemetry experiment with representative fishery‐dependent survey data. Scientific personnel and industry partners collected data on a suite of biological, environmental, and technical covariates from 2,442 Haddock caught under authentic fishery scenarios during 2015. Despite being a physoclistous species, <1% of sampled Haddock were observed to die when brought onboard and only ~3% floated upon release. Postrelease fate was then monitored for 154 Haddock using passive acoustic telemetry and determined using a semiquantitative classification procedure reliant upon movement data of Haddock with known fates. The resulting data were analyzed with a parametric survival model to identify which capture‐related covariates influenced mortality. Fishing season and length‐class of Haddock were the most significant predictors of discard mortality, with increased mortality for smaller individuals caught during the autumn, possibly due to increased temperatures. Survival modeling identified that mortality from these covariates occurred primarily after release as compared with during capture and handling. By integrating survival modeling results with fishery‐dependent observations, a fishery‐scale discard mortality rate of 63% was estimated for the 2015 fishing year. Based on these findings, we recommend that fishery managers implement measures to reduce recreational Haddock discards, especially of smaller Haddock during warmer months.

AbstractAn overall lack of information prompted the recent listing of Atlantic Sturgeon Acipenser oxyrinchus oxyrinchusunder the Endangered Species Act. Key to the restoration of the species and of particular importance is the need to characterize the use of critical habitat across the region, specifically in the Gulf of Maine, where the population was listed as threatened. Much of the research to date has focused on large river systems able to support remnant spawning populations; however, the role of small coastal river systems for Atlantic Sturgeon is not well documented. Several of these systems are being reinhabited, and to facilitate new knowledge about the Gulf of Maine population, a long-term (2009–2014) acoustic telemetry study for 51 Atlantic Sturgeon tagged in the Saco River was evaluated. Results suggested that the majority of fish were aggregating near the natural mouth of the estuary across the 6 years. Gastric lavage samples from 163 (91 juvenile and 72 adult) fish (65.0–171.5 cm fork length) during 2013 and 2014 demonstrated that American Sand Lance Ammodytes americanuswas the most common prey (the index of relative importance for 2013 and 2014 was 93.5% and 85.4%, respectively), a finding unique to this river system. In addition, benthic sediment grabs, beam trawls, otter trawls, and beach seines conducted in 2013 and 2014 indicated that the distribution of American Sand Lances was comparable to the aggregation area observed for Atlantic Sturgeon. The combined results suggest that the Saco River estuary provides critical foraging habitat imperative for the future recovery of the Gulf of Maine Atlantic Sturgeon population.Received May 24, 2016; accepted November 17, 2016 Published online February 15, 2017

An overall lack of information prompted the recent listing of Atlantic Sturgeon Acipenser oxyrinchus oxyrinchusunder the Endangered Species Act. Key to the restoration of the species and of particular importance is the need to characterize the use of critical habitat across the region, specifically in the Gulf of Maine, where the population was listed as threatened. Much of the research to date has focused on large river systems able to support remnant spawning populations; however, the role of small coastal river systems for Atlantic Sturgeon is not well documented. Several of these systems are being reinhabited, and to facilitate new knowledge about the Gulf of Maine population, a long-term (2009–2014) acoustic telemetry study for 51 Atlantic Sturgeon tagged in the Saco River was evaluated. Results suggested that the majority of fish were aggregating near the natural mouth of the estuary across the 6 years. Gastric lavage samples from 163 (91 juvenile and 72 adult) fish (65.0–171.5 cm fork length) during 2013 and 2014 demonstrated that American Sand Lance Ammodytes americanuswas the most common prey (the index of relative importance for 2013 and 2014 was 93.5% and 85.4%, respectively), a finding unique to this river system. In addition, benthic sediment grabs, beam trawls, otter trawls, and beach seines conducted in 2013 and 2014 indicated that the distribution of American Sand Lances was comparable to the aggregation area observed for Atlantic Sturgeon. The combined results suggest that the Saco River estuary provides critical foraging habitat imperative for the future recovery of the Gulf of Maine Atlantic Sturgeon population. Received May 24, 2016; accepted November 17, 2016 Published online February 15, 2017

AbstractEvidence has become available in this century indicating that populations of the endangered Shortnose Sturgeon Acipenser brevirostrummigrate outside their natal river systems, but the full extent and functional basis of these migrations are not well understood. Between 2007 and 2013, 40 Shortnose Sturgeon captured and tagged in four Gulf of Maine river systems migrated long distances in coastal waters to reach the Kennebec System where their movements were logged by an acoustic receiver array. Twenty-one (20%) of 104 Shortnose Sturgeon tagged in the Penobscot River, two (50%) of four tagged in the Kennebec System, one (50%) of two tagged in the Saco River, and 16 (37%) of 43 tagged in the Merrimack River moved to a previously identified spawning site or historical spawning habitat in the Kennebec System in spring. Most (65%) moved in early spring from the tagging location directly to a spawning site in the Kennebec System, whereas the rest moved primarily in the fall from the tagging location to a wintering site in that system and moved to a spawning site the following spring. Spawning was inferred from the location, behavior, and sexual status of the fish and from season, water temperature, and discharge, and was confirmed by the capture of larvae in some years. Tagged fish went to a known spawning area in the upper Kennebec Estuary (16 events) or the Androscoggin Estuary (14 events), an historical spawning habitat in the restored Kennebec River (8 events), or two spawning areas in a single year (7 events). We have provided the first evidence indicating that Shortnose Sturgeon spawn in the restored Kennebec River in an historical habitat that became accessible in 1999 when Edwards Dam was removed, 162 years after it was constructed. These results highlight the importance of the Kennebec System to Shortnose Sturgeon throughout the Gulf of Maine.Received October 10, 2014; accepted March 30, 2015

Evidence has become available in this century indicating that populations of the endangered Shortnose Sturgeon Acipenser brevirostrummigrate outside their natal river systems, but the full extent and functional basis of these migrations are not well understood. Between 2007 and 2013, 40 Shortnose Sturgeon captured and tagged in four Gulf of Maine river systems migrated long distances in coastal waters to reach the Kennebec System where their movements were logged by an acoustic receiver array. Twenty-one (20%) of 104 Shortnose Sturgeon tagged in the Penobscot River, two (50%) of four tagged in the Kennebec System, one (50%) of two tagged in the Saco River, and 16 (37%) of 43 tagged in the Merrimack River moved to a previously identified spawning site or historical spawning habitat in the Kennebec System in spring. Most (65%) moved in early spring from the tagging location directly to a spawning site in the Kennebec System, whereas the rest moved primarily in the fall from the tagging location to a wintering site in that system and moved to a spawning site the following spring. Spawning was inferred from the location, behavior, and sexual status of the fish and from season, water temperature, and discharge, and was confirmed by the capture of larvae in some years. Tagged fish went to a known spawning area in the upper Kennebec Estuary (16 events) or the Androscoggin Estuary (14 events), an historical spawning habitat in the restored Kennebec River (8 events), or two spawning areas in a single year (7 events). We have provided the first evidence indicating that Shortnose Sturgeon spawn in the restored Kennebec River in an historical habitat that became accessible in 1999 when Edwards Dam was removed, 162 years after it was constructed. These results highlight the importance of the Kennebec System to Shortnose Sturgeon throughout the Gulf of Maine.