ObjectiveIn recent years, electronic self-reporting has emerged as a potentially powerful tool for timely collection of catch and effort data from recreational fisheries. Such approaches are particularly critical given that recreational fisheries contribute significantly to fishing mortality for popular marine fish species in North America and elsewhere. However, many self-reporting programs are voluntary and struggle with angler recruitment and retention, while those that are mandatory have demonstrated mixed success with angler compliance. In this study, we surveyed Massachusetts anglers in the recreational fishery for Atlantic Bluefin Tuna Thunnus thynnus; anglers in this fishery are required to report all landings and dead discards, but compliance has historically been poor.MethodsThe survey assessed respondents' Bluefin Tuna fishing experience and behavior, opinions about self-reporting, and views on the effectiveness of various strategies to increase self-reporting rates. Because we had access to past reporting history, we were able to compare responses between those who had previously reported Bluefin Tuna and those who had not.ResultWe achieved a response rate of 21.9%, and by comparing survey responses with past reporting history, we estimated a reporting compliance rate of only about 42%. Surprisingly, responses to survey questions generally did not differ markedly between reporters and nonreporters, although we did find evidence that those who complied with the self-reporting requirement had less faith in the Bluefin Tuna fishery's management process. Among the top strategies identified by respondents to increase reporting compliance were (1) providing incentives; (2) providing behavioral "nudges," such as reminders; (3) better educating anglers on the benefits of self-reporting; (4) increasing the user-friendliness of the reporting technology; and (5) the reframing of norms through leveraging leaders in the fishery.ConclusionOur findings can help to inform self-reporting and other citizen science approaches to maximize the quantity and quality of recreational data collected, in turn informing the sustainable management of this sector. Effectively estimating the number of fish caught by recreational anglers is key for sustainably managing fishery resources, and electronic self-reporting approaches such as smartphone apps could help managers better monitor catch. However, these tools depend on high levels of participation by anglers. This study identified strategies that managers could employ to improve self-reporting rates in the recreational Atlantic Bluefin Tuna fishery in Massachusetts, which could be applied to other fisheries as well.Impact statement

Interactions between spatial dynamics and stock structure in marine fishes have largely focused on stocks in decline; stock structure is rarely re-visited for expanding species. Here, the spatial ecology of Atlantic halibut (Hippoglossus hippoglossus L.), managed as four stocks in the Northwest Atlantic, is reviewed. Halibut collapsed under high exploitation in the mid-19th century, but the Canadian fisheries value has increased seven-fold since the early 2000s. Atlantic halibut's thermal habitat has increased due to warming, possibly contributing to its expansion. Genomic evidence differentiates two populations in the four management units, whereas there is non-genetic spatial structure within each of the stock boundaries. There are different core juvenile areas and a diversity of spawning migration patterns influenced by timing, fish size, maturity state, and distance between summer-feeding and over-wintering habitats. From tagging studies, multiple estimates of median distance at recapture (similar to 3-90 km) are much less than the spatial domain of each stock. Growth rates are faster in the warmer south, as predicted by growing degree day. The current perspective of Atlantic halibut spatial structure is that there are two distinct populations, and within each, there are subpopulations composed of multiple migratory contingents. The level of mixing on common spawning grounds both among and within subpopulations is only partly understood.

The data-limited nature of Atlantic halibut (Hippoglossus hippoglossus) in U.S. waters hampers evaluation of what may be a slow but steady rebuilding pattern. Here, we collaborate with the commercial fishery to design and implement a multi-gear sampling program that collected 100s of biological samples from throughout the Gulf of Maine in a five-year period, 2014–2018. Examination of sectioned otoliths revealed a maximum age of 12 years (females) and 13 years (males); in comparison, Atlantic halibut as old as 40–50 years have been collected elsewhere in the western North Atlantic. Growth modeling confirmed sexual dimorphism, with a larger asymptotic length (L∞) for females (214 cm fork length [FL]) than males (195 cm FL). Estimates of median female length at maturity, L50, of 128 cm FL (124–132 cm, 95% confidence limits), and median female age at maturity, A50, of 9.6 years old (9.0–10.8 years), were longer and older than previous reports for the Gulf of Maine, likely resulting from our use of histological instead of macroscopic methods to classify maturity. Histology demonstrated that vitellogenesis initiated in individuals in spring, nearly a year prior to spawning, which allowed us to identify first-time (primiparous) spawners and provided the first potential evidence of skip spawning for this species. Finally, an index was developed to track the proportion of potentially mature females in the fishery, which showed an increasing trend; this qualitative tool may prove useful in a data-limited environment for evaluating the relative stock status of Atlantic halibut.

Within fisheries, stakeholders often have varying viewpoints regarding natural marine resources, and use different sets information to evaluate their condition. Evaluating a resource with different sets of information can lead to different conclusions. Windowpane flounder (Scophthalmus aquosus) are a managed finfish species in the northwest Atlantic whose regulations have the potential to limit harvest opportunities for target species. We analyzed commercial trip and catch information from video data to understand local densities of windowpane flounder in conjunction with fisheries independent surveys. Video monitoring data from three Rhode Island commercial fisher's vessels and fisheries independent trawl survey data were analyzed to understand the geographic distribution of the stock as well as overlap with temporary closed areas. Biomass data from the fisheries-dependent and fisheries-independent surveys were combined with a spatial-temporal model that accounted for differences in catchability among vessels and spatial autocorrelation. A separate analysis of estimated discard rates with observer data was also conducted to determine how the distribution of windowpane discards in Southern New England compared to the distribution of model predicted windowpane abundance. In agreement with the fishermen's observations, the temporary closed areas were not located where the highest densities of windowpane flounder occurred. The temporary closed areas, however, were located where the highest rates of discards occurred and thus where fishing had the greatest impact on the stock. The integration of verified fishery-dependent data with the scientific surveys has the potential to create a single set of information that is trusted by all user groups.

Douglas R. Zemeckis *, Micah J. Dean, Annamaria I. DeAngelis, Sofie M. Van Parijs, William S. Hoffman, Mark F. Baumgartner, Leila T. Hatch, Steven X. Cadrin, and Christopher H. McGuire School for Marine Science and Technology University of Massachusetts Dartmouth, 836 South Rodney French Boulevard, New Bedford, MA 02744, USA Annisquam River Marine Fisheries Field Station Massachusetts Division of Marine Fisheries, 30 Emerson Avenue, Gloucester, MA 01930, USA Protected Species Branch Northeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 166 Water Street, Woods Hole, MA 02543, USA Integrated Statistics, 16 Sumner Street, Woods Hole, MA 02543, USA Biology Department, Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543, MS #33, USA Stellwagen Bank National Marine Sanctuary, National Ocean Service, National Oceanic and Atmospheric Administration, 175 Edward Foster Road, Scituate, MA 02066, USA The Nature Conservancy, 99 Bedford Street, 5th Floor, Boston, MA 02111, USA *Corresponding author: tel: þ1-732-349-1152; e-mail: zemeckis@njaes.rutgers.edu. Present Address: Department of Agriculture and Natural Resources, New Jersey Agricultural Experiment Station Rutgers The State University of New Jersey,1623 Whitesville Road, Toms River, NJ 08755, USA.

Effective fishery management measures to protect fish spawning aggregations require reliable information on the spatio-temporal distribution of spawning. Spawning closures have been part of a suite of fishery management actions to rebuild the Gulf of Maine stock of Atlantic cod (Gadus morhua), but difficulties remain with managing rebuilding. The objective of this study was to identify the spatial and temporal distribution of cod spawning during winter in Massachusetts Bay to improve our understanding of cod spawning dynamics and inform fisheries management. Spawning was investigated in collaboration with commercial fishermen during three winter spawning seasons (October 2013-March 2016) using acoustic telemetry and passive acoustic monitoring equipment deployed in fixed-station arrays and mounted on mobile autonomous gliders. Tagged cod exhibited spawning site fidelity and spawning primarily occurred from early November through January with a mid-December peak and some inter-annual variability. The spatial distribution of spawning was generally consistent among years with multiple hotspots in areas >50m depth. Current closures encompass most of spawning, but important areas are recommended for potential modifications. Utilizing multiple complementary technologies and deployment strategies in collaboration with commercial fishermen enabled a comprehensive description of spawning and provides a valuable model for future studies.

Atlantic halibut are a “Species of Concern” in US waters and little is known about their movements and stock structure. Recent stock assessments drew attention to the paucity of information for assessing and managing this stock. To investigate movement patterns and stock structure, halibut were tagged off Massachusetts and Maine within US waters of the Gulf of Maine region using pop-up satellite archival tags and data storage tags. A hidden Markov model (HMM) geolocation method previously developed for other groundfish species was adapted to estimate the movement tracks of the tagged halibut (n = 25) based on the tag-recorded depth and temperature. Total distance travelled based on geolocation ranged from 36 to 1701 km, whereas straight line distance between tagging and end locations ranged from 0.4 to 440.7 km. Estimated movement rates varied between 2.7 and 10 km day−1. Two tagged halibut made long-distance movements to putative spawning habitat in the Northeast Channel off Georges Bank. Thirteen (13) out of 25 geolocated individuals were estimated to have reached Canadian waters. Geolocation results revealed home range, return movement, and seasonal migration movement patterns exhibited by the tagged halibut. The HMM geolocation method could be a useful tool in providing information on halibut movements that can inform stock assessment and management decisions.

Many studies illustrate variable patterns in individual species distribution shifts in response to changing temperature. However, an assemblage, a group of species that shares a common environmental niche, will likely exhibit similar responses to climate changes, and these community-level responses may have significant implications for ecosystem function. Therefore, we examine the relationship between observed shifts of species in assemblages and regional climate velocity (i.e., the rate and direction of change of temperature isotherms). The assemblages are defined in two sub-regions of the U.S. Northeast Shelf that have heterogeneous oceanography and bathymetry using four decades of bottom trawl survey data and we explore temporal changes in distribution, spatial range extent, thermal habitat area, and biomass, within assemblages. These sub-regional analyses allow the dissection of the relative roles of regional climate velocity and local physiography in shaping observed distribution shifts. We find that assemblages of species associated with shallower, warmer waters tend to shift west-southwest and to shallower waters over time, possibly towards cooler temperatures in the semi-enclosed Gulf of Maine, while species assemblages associated with relatively cooler and deeper waters shift deeper, but with little latitudinal change. Conversely, species assemblages associated with warmer and shallower water on the broad, shallow continental shelf from the Mid-Atlantic Bight to Georges Bank shift strongly northeast along latitudinal gradients with little change in depth. Shifts in depth among the southern species associated with deeper and cooler waters are more variable, although predominantly shifts are toward deeper waters. In addition, spatial expansion and contraction of species assemblages in each region corresponds to the area of suitable thermal habitat, but is inversely related to assemblage biomass. This suggests that assemblage distribution shifts in conjunction with expansion or contraction of thermal habitat acts to compress or stretch marine species assemblages, which may respectively amplify or dilute species interactions to an extent that is rarely considered. Overall, regional differences in climate change effects on the movement and extent of species assemblages hold important implications for management, mitigation, and adaptation on the U.S. Northeast Shelf.