Search results for "fish"

Replicated marine protected areas (MPAs) support movement of larger, but not more, European lobsters to neighbouring fished areas

2018

The European lobster Homarus gammarus is heavily exploited in the Norwegian fishery, and several management actions have been implemented to protect the species. Three marine protected areas (MPAs) excluding all but hook and line type fishing gear were established along the Skagerrak coast in 2006, effectively banning the trap-based fishery for European lobster. Lobster populations within MPAs and adjacent control areas were studied by capture-mark-recapture and recovery methods every year from prior to MPA establishment to the present. During 2006-2014, a total of 4682 and 3317 lobsters were captured (including recaptures) in the MPAs and control areas, respectively. In all MPAs, protectio…

Size-dependent predation of the mesopredator Marthasterias glacialis (L.) (Asteroidea)

2016

Asteroids are largely recognized as important predators in all of the world’s oceans and for this reason, they play a crucial role in shaping the structure and functioning of benthic ecosystems. The spiny starfish Marthasterias glacialis is generally considered a voracious predator of molluscs, in particular bivalves. Using field observations and carbon (δ13C) and nitrogen (δ15N) stable isotopes, we explored possible changes in diet in relation to size of M. glacialis. Data were collected at Ustica Island (Southern Tyrrhenian Sea) from June 2008 to June 2010. M. glacialis showed a size shift in feeding preferences due to different use of food items: bivalves, Columbella rustica, Euthria cor…

Afforested fields benefit nutrient-demanding fungi

2015

Impaired ecosystems are converted back to natural ecosystems or some other target stage by means of restoration and management. Due to their agricultural legacy, afforested fields might be valuable compensatory habitats for rare fungal species that require nutrient-rich forest soils. Using a large-scale field experiment in Finland, we studied community composition of macrofungi (agarics and boletes) on former fields, which had been afforested as monocultures 20 years ago using native spruce Picea abies, pine Pinus sylvestris, and birch Betula pendula. We studied the effect of soil quality, tree species, and site on community composition and structure. Many nutrient-demanding as well as rare…

Sex- and size-selective harvesting of corkwing wrasse (Symphodus melops)—a cleaner fish used in salmonid aquaculture

2016

Fishery-induced changes in sex ratios can have negative effects on reproductive rates and affect sexual selection and evolutionary trajectories. Here, we investigate sex- and size-selectivity of the fishery for corkwing wrasse (Symphodus melops) in Western Norway. The males that build and guard nests (nesting males) grow faster than females and sneaker males. Corkwing wrasse were tagged (n = 1057) during (May–June) and after (July) the spawning period in 2014 within a no-take site and in a nearby site open for fishing. We monitored the fishery within and nearby the tagging sites from June to October and sampled recaptures on all commercial fishing trips. Fishing mortality was higher for nes…

2021

Without insights into the threats affecting species across their distributions and throughout their annual cycles, effective conservation management cannot be applied. The Whenua Hou diving petrel Pelecanoides whenuahouensis (WHDP) is a Critically Endangered small seabird whose offshore habits and threats are poorly understood. We tracked WHDPs year-round in 2015/16, 2017/18, and 2018/19 using global location-sensing immersion loggers to identify offshore distribution, movements, behaviour, and overlap with commercial fishing effort. During the breeding period, WHDPs ranged from southern Aotearoa (New Zealand) to Maukahuka (Auckland Islands). After breeding, WHDPs migrated southwest towards…

Control of off-flavor compounds in a full-scale recirculating aquaculture system rearing rainbow trout Oncorhynchus mykiss

2020

Fish is increasingly produced in recirculating aquaculture systems (RAS), which can offer some production and environmental benefits. Unfortunately, there is a tendency to develop off-flavors in RA...

Proposing a Technical Solution for Restoring Longitudinal Connectivity in the Brădeni/Retiş Accumulation Area on Hârtibaciu River

2016

Abstract The fish fauna of the Hârtibaciu River has experienced a disrupted connectivity due to the hydrotechnical works and the Brădeni/Retiş Dam located across the Hârtibaciu watercourse being one of this significant obstacles. The newly proposed constructed wetlands can improve the habitat quality for the fish species of conservative interest sampled in the Brădeni/Retiş Dam proximity Rhodeus amarus, and can increase the individuals’ number of this population. Also can benefit the local populations of Phoxinus phoxinus and Gobio obtusirostris. Using gravitational force and also the underground layout, a proposed technical solution gives maximum safety regarding the water supply for the n…

Temporal variability in offspring quality and individual reproductive output in a broadcast-spawning marine fish

2017

Abstract The protracted spawning period of broadcast-spawning marine fishes has potential to generate considerable variability in metrics of individual reproductive output. We undertook a temporally detailed genetic study of larvae produced by Atlantic cod (Gadus morhua) from two spatially proximate populations spawning under controlled semi-natural conditions over 94 days. Based on daily samples of larvae (n = 4489 in total), we document fine-scaled temporal changes in, and correlates of, offspring phenotype and reproductive output (egg batches produced or fertilized). Larval length and standardized yolk-sac volume declined 11 and 49% over the spawning period, respectively. The adaptive si…

The use of a spatial model of economic efficiency to predict the most likely outcomes under different fishing strategy scenarios

2021

The current European Union has been progressively implementing since January 2014 a discard ban which includes the obligation to land unwanted catch for certain regulated species and sizes. Although a full enforcement of the landing obligation has a direct impact on discard reduction through more responsible and selective fishing, fishers argue that it will prompt both a decrease in incomes and an increase in working time onboard. Thus, the measure is in a hold in south-western waters due to the difficulties to implement the ban in mixed fisheries This paper analyzes some possible scenarios which fishers could face under the landing obligation. It is shown the construction of a spatial bio-…

Assessing the added value of the recent declaration on unregulated fishing for sustainable governance of the central Arctic Ocean

2016

Accepted manuscript version. Published version available at https://doi.org/10.1016/j.marpol.2016.01.013. Accepted manuscript version, licensed CC BY-NC-ND 4.0. The ‘Declaration concerning the prevention of unregulated high seas fishing in the central Arctic Ocean’ signed by the Arctic 5 nations, limits unregulated high seas fishing in the central part of the Arctic Ocean, and holds potential social, economic and political impacts for numerous stakeholders. In this paper, the four Interim Measures in the Declaration are discussed and what value these measures bring beyond the existing international agreements is explored. It is found that even though the Declaration fills a gap in the manag…