Search results for "fishery"
showing 10 items of 591 documents
Reproduction of Baltic cod, Gadus morhua (Actinopterygii: Gadiformes: Gadidae), in the Gotland Basin: Causes of annual variability
2015
Background. The Gotland Basin spawning ground is one of three main spawning areas of Baltic cod, Gadus morhua Linnaeus, 1758. The threshold water parameters for cod development are the salinity exceeding 11‰ and the oxygen level above 2 mL· L–1. Such conditions are only present when the 11‰ isohaline is above the 2 mL· L–1 isooxygen. In such situation the water volume between the isolines is called the “suitable reproduction volume”. When the position of the isolines is reversed, the salinity and the oxygen level of the water layer demarcated by them are below the required thresholds and as such the water is unsuitable for the cod development. We refer to it as the “unsuitable reproduction …
Learning and remembering the environment in the blind cave fishAnoptichthys jordani
1989
1. The swimming behavior of blind cave fish (Anoptichthys jordani) differs in familiar and unfamiliar surroundings. Following release in unfamiliar surroundings, or after alterations of a familiar environment, the fish increase swimming velocity in order to optimize lateral line organ stimulation. Furthermore, they glide along boundary features more often than they do in familiar surroundings. These characteristics of swimming behavior were used to measure the occurrence and duration of exploratory behavior. 2. Fish removed from a familiar environment for as long as 2 days spend less time exploring when returned than when they were initially placed in the environment. After a longer absence…
The role of eutrophication reduction of two small man-made Mediterranean lagoons in the context of a broader remediation system: Effects on water qua…
2013
In order to meet the requirements of the European Union Water Framework Directive for the Albufera de Valencia (AV) Natural Park, in 2009, several areas of free water surface constructed wetlands (FWSCWs) planted with emergent vegetation and two small shallow lagoons planted with submerged macrophytes were created over a 40-ha area formerly occupied by rice fields. This area is currently a reserve known as Tancat de la Pipa. The dual goal of this programme was to improve the quality of the hyper-eutrophicated waters of the AV lagoon, the largest littoral lagoon in the Iberian Peninsula, and to restore former lost habitats to increase the biodiversity of the area. The lagoons were mainly fed…
Dynamics of Ostracoda (Crustacea) assemblages in a Mediterranean pond system (Racó de l'Olla, Albufera Nat. Park) with focus on the exotic speciesCan…
2013
Coastal pond systems can account for a rich aquatic faunal diversity and complex functioning due to interplay between freshwater wetlands and marine influences. Within the large Albufera wetland Natural Park, Raco de l'Olla is constituted by a set of permanent and temporary ponds with strict protection level for migrating bird conservation. Its terrestrial faunal diversity and dynamics has been partially characterized in previous studies, but nothing was known about its ostracod communities. Benthic samples collected monthly for 1 year in 11 points through the pond system, together with limnological information, allowed establishing a sound knowledge on its ostracod community and population…
Artificial Reefs in Sicily: An Overview
2000
Sicilian cave drawings from the Grotta del Genovese, Isle of Levanzo (west Sicily) ca. 12 000 B.C. show silhouettes of dolphins, tuna, groupers and bass which, together with remains offish (tuna, groupers, bass and others), limpets and oysters from Grotta dell Uzzo, north-western Sicily, indicate the importance of fish and shellfish in the diet of coastal populations of that time (Villari, 1992a, 1992b). Remains of turtles (Caretta caretta), tuna and sharks are evidence of fishing activity during this period (Villari, 1995).
Subsurface swimming and stationary diving are metabolically cheap in adult Pacific walruses (Odobenus rosmarus divergens).
2021
ABSTRACT Walruses rely on sea-ice to efficiently forage and rest between diving bouts while maintaining proximity to prime foraging habitat. Recent declines in summer sea ice have resulted in walruses hauling out on land where they have to travel farther to access productive benthic habitat while potentially increasing energetic costs. Despite the need to better understand the impact of sea ice loss on energy expenditure, knowledge about metabolic demands of specific behaviours in walruses is scarce. In the present study, 3 adult female Pacific walruses (Odobenus rosmarus divergens) housed in professional care participated in flow-through respirometry trials to measure metabolic rates while…
Sabanejewia Aurata (De Filippi, 1863) Populations Management Decisions Support System for Rosci0132 (Olt River Basin)
2015
Abstract The ADONIS: CE was used to design a specific management model for the Sabanejewia aurata (De Filippi, 1863) populations. The proposed model is based on this species, in situ identified biological/ecological necessities in relation to the habitats, the conservation status indicators and appropriate management actions and the pressures and threats founded in the study area. Such on species, on habitats and on site based management system was done to complete this approach for ROSCI0132, the other fish species which are living there being treated already in this respect.
Cottus gobio Linnaeus, 1758 Community Interest Species Conservation in Upper Târnava Mare River Basin, Through Fish Populations Rehabilitation for Br…
2017
Abstract The ADONIS: CE software has been used for two fish species, Cottus gobio, of conservation interest and Salmo trutta fario, of economic interest, to design an on-site (upper Târnava Mare River) adapted support-system model for management decision-making. Habitat needs and indicators of favourable conservation status have been investigated, pressures and threats to these fish species have been determined, and management elements have been suggested. This management system allows the proper organization of management measures for the renaturation of the local natural fish associations in the local brown trout zone.
Trophic cascades in benthic marine ecosystems: lessons for fisheries and protected-area management
2000
An important principle of environmental science is that changes in single components of systems are likely to have consequences elsewhere in the same systems. In the sea, food web data are one of the few foundations for predicting such indirect effects, whether of fishery exploitation or following recovery in marine protected areas (MPAs). We review the available literature on one type of indirect interaction in benthic marine ecosystems, namely trophic cascades, which involve three or more trophic levels connected by predation. Because many indirect effects have been revealed through fishery exploitation, in some cases we include humans as trophic levels. Our purpose is to establish how wi…
Density Decline in a Mediterranean Seahorse Population: Natural Fluctuations or New Emerging Threats?
2021
Illegal wildlife trade is considered one of the most serious threats to biodiversity worldwide, along with habitat loss/degradation and overfishing of wild stocks. Seahorses are considered at high risk as these fish represent an important component of traditional Chinese medicine but are also sold as curios and ornamental fish. On a worldwide level, illegal trade is controlled by numerous laws and regulations, but it seems to continue by assuming more dynamic routes. In the Mediterranean Sea, Hippocampus guttulatus formed one of the largest populations at Mar Piccolo di Taranto in South-Eastern Italy. During the routine monitoring of this population in 2016, a dramatic density decrease was …