With the growing grey seal population in the Baltic Sea, the inshore cod fishery has suffered dramatic increases in both catch losses and damage to fishing gear. To mitigate this situation, cod pots were evaluated as an alternative to traditional gillnets and longlines. During a 3-year study, cod pots were used by commercial fishers in two areas off the coast of Sweden. Using the...
Fish and invertebrates that are unintentionally captured during commercial fishing operations and then released back into the ocean suffer mortality at unknown rates, introducing uncertainty into the fishery management process. Attempts have been made to quantify discard mortality rates using reflex action mortality predictors or RAMP which use the presence or absence of a suite...
The High Seas are increasingly the subject of exploitation. Although Marine Protected Areas (MPAs) are seen as a useful tool in the sustainable management of the oceans, progress in the implementation of MPA networks in areas beyond national jurisdiction has been limited. Specifically, the criteria of “representativeness” has received little consideration. This study uses the...
We estimate temporal variation in fecundity, the reproduction rate, for Barents Sea and Greenland Sea harp seals using a state–space approach. A stochastic process model for fecundity is integrated with an age-structured population dynamics model and fit to available data for these two harp seal populations. Owing to scarceness of data, it is necessary to “borrow strength” from...
Three primary factors affecting genetic patterns of marine species in the Northwestern Pacific Ocean have been proposed: isolation and population expansion during Pleistocene glacial cycles, ocean currents facilitating the gene flow, and the Yangtze River outflow imposing a physical barrier to gene flow. Here, we examined these factors affecting population structuring of the...
Abundances of semi-pelagic fish are often estimated using acoustic or bottom trawl surveys, both of which sample only a fraction of the water column. Acoustic instruments are effective at sampling the majority of the water column, but they have a near-surface blind zone and a near-bottom acoustic dead zone (ADZ), where fish remain undetected. Bottom trawls are effective near the...
Acoustic survey methods are useful to estimate the distribution, abundance, and biomass of mesopelagic fish, a key component of open ocean ecosystems. However, mesopelagic fish pose several challenges for acoustic biomass estimation based on their small size, wide depth range, mixed aggregations, and length-dependent acoustic reflectance, which differentiate them from the larger...
Stocking with eggs has been widely used as a management measure to support degraded salmonid stocks. In Finland, Atlantic salmon and both sea-migrating and lake-migrating brown trout are stocked as eggs, alevins, fry, parr, and smolt, whereas trout are also stocked as mature fish. The aim of this stocking is to improve catches and to support collapsed spawning stocks. We assessed...
Leptocephali, the larvae of eels, grow to large sizes and are widely distributed in tropical and subtropical oceans. Their role in oceanic food webs is poorly known because they are rarely reported as food items in fish stomach content studies. Data from 13 years of research on the trophic dynamics of Pacific Ocean predatory fish indicate that among 8746 fish of 76 species/taxa...
Ecosystem-based fisheries management seeks to consider trade-offs among management objectives for interacting species, such as those that arise through predator–prey linkages. In particular, fisheries-targeting forage fish (small and abundant pelagic fish) might have a detrimental effect on fisheries-targeting predators that consume them. However, complexities in ecological...
Indices of abundance are the bedrock for stock assessments or empirical management procedures used to manage fishery catches for fish populations worldwide, and are generally obtained by processing catch-rate data. Recent research suggests that geostatistical models can explain a substantial portion of variability in catch rates via the location of samples (i.e. whether located...
Implementation of single-species catch limits in multispecies individual quota systems is problematic because it may incentivize discarding behaviour when quotas for some species limit catch of jointly caught species. Since discarding may reduce economic benefits and bias stock assessments, mechanisms that reduce incentives to discard can be beneficial. However, these mechanisms...
Fisheries biology encompasses a tremendous diversity of research questions, methods, and models. Many sub-fields use observational or experimental data to make inference about biological characteristics that are not directly observed (called “latent states”), such as heritability of phenotypic traits, habitat suitability, and population densities to name a few. Latent states will...
In this essay, I review six decades of my career in marine science and fisheries, considering the ideas that came and went in the period as “food for thought”. I describe my inspirations and successes, and my disappointments and failures. My activities were both administrative and research-oriented. As regards the former, I was part of major changes in ocean policy and new ocean...
Part of the European Union (EU) Common Fisheries Policy revision of 2013 is a commitment to implement a land-all policy, under which the practice of discarding caught fish back into the sea will be forbidden. This measure will be applied first to the pelagic fleet in 2015, with a phased implementation for the demersal fleet between 2016 and 2019. As part of trials to determine...
The difficulty of ensuring adequate statistical coverage of whole fleets is a challenge for the implementation of observer programmes and may reduce the usefulness of the data they obtain for management purposes. This makes it necessary to find cost-effective alternatives. Electronic monitoring (EM) systems are being used in some fisheries as an alternative or a complement to...
The walleye pollock (Gadus chalcogrammus) fishery in the Bering Sea is one of the largest fisheries in the world. The North Pacific Fishery Management Council (NPFMC) provides management advice for this fishery, including the development of measures to minimize salmon bycatch to the extent practicable, one of the stated objectives of the US Magnuson–Stevens Fishery Conservation...
Chinook salmon (Oncorhynchus tshawytscha) are taken as bycatch in the Bering Sea pollock (Gadus chalcogrammus) fishery, with recently revised management measures in place to limit the overall Chinook salmon catch. Historical impact of the bycatch on regional salmon stocks is made difficult because, until recently, sampling for the stock composition of the bycatch was patchy and...
In this paper, we synthesize information presented at the 2nd Fishery Dependent Information (FDI) Conference, held in Rome, Italy, from 2 to 6 March 2014. We review current issues and advances in the collection, interpretation and application of fishery-dependent data, and highlight emergent findings in the field. Key issues include (i) the design and collection of data...
Implementing marine ecosystem-based management at regional and small spatial scales is challenging due to the complexity of ecosystems, human activities, their interactions and multilayered governance. Ecological risk assessments (ERAs) of marine biodiversity are often used to prioirtise issues but only give broad guidance of how issues might be addressed in the form of...
Ecosystem-based management (EBM) is promoted as the solution for sustainable use. An ecosystem-wide assessment methodology is therefore required. In this paper, we present an approach to assess the risk to ecosystem components from human activities common to marine and coastal ecosystems. We build on: (i) a linkage framework that describes how human activities can impact the...
A development of the ecological risk screening (ERS) technique, scale intensity and consequence analysis (SICA), is described and application to the varied fisheries and ecosystem off the southwest of England on behalf of an industry steering group (SG) is summarized. The purpose was to prioritize ecological risks systematically and consistently in relation to policy goals agreed...
We evaluated two risk models (bioregion pathway and species-based exposure), with the aim to determine an effective strategy to implement marine biosecurity risk management in regions/countries where biological data are limited. We used the Port of Tanjung Priok, Jakarta Bay, Indonesia, as a case study to test both models. The bioregion pathway model illustrates that Tanjung...
Indonesia is a biodiversity hotspot threatened with new introductions of marine species. As with many countries, Indonesia has a stratified shipping network of international ports linked to a large suite of domestic ports. We developed a hub and spoke network model to examine the risk associated with the secondary transfer of introduced marine species from the port hub of Tanjung...
We review three broad categories of risk assessment methodology used for cartilaginous fish: productivity-susceptibility analysis (PSA), demographic methods, and quantitative stock assessments. PSA is generally a semi-quantitative approach useful as an exploratory or triage tool that can be used to prioritize research, group species with similar vulnerability or risk, and provide...