Fish Ecology

La pesca durant l'edat mitjana a través de les fonts literàries catalanes

by Frederic Aparisi Romero

Fishing in the middle ages is a subject that has interested the Spanish historiography recently. However, a paper... more Fishing in the middle ages is a subject that has interested the Spanish historiography recently. However, a paper about the sources and the work lines that the historianshave to study it has not done yet. This paper is an attempt to revise the sources of Catalan literature produced during the 13th and 15th Centuries trying to concrete the considerations about the fish and fishing in the Crown of Aragon in this period.

Macreadie et al. 2012 Frontiers Write Back

by Peter Macreadie

Rigs-to-reefs policy: can science trump public sentiment?

Frontiers in Ecology and the Environment

Peter I Macreadie*, Ashley M Fowler, and David J Booth
School of the Environment, University of Technology,... more Peter I Macreadie*, Ashley M Fowler, and David J Booth
School of the Environment, University of Technology, Sydney, Australia *(peter.macreadie@uts.edu.au)

Hortle 2008 Yield and value of the wild fishery of rice fields in Battambang Province, Cambodia

by Kent Hortle

Hortle 1989 Use of emetics to obtain stomach contents of the rock flagtail, Kuhlia Rupestris Bull Aust Soc Limnol 12

by Kent Hortle

Metapopulation dynamics of a diadromous galaxiid fish and potential effects of salmonid aquaculture

by Sofia (Sonia) Consuegra del Olmo

Niche segregation in two closely related species of stickleback along a physiological axis: Explaining multidecadal changes in fish distribution from iron-induced respiratory impairment.

by Wilco Verberk

Aquatic Ecology in press, doi: 10.1007/s10452-012-9395-y

Acute exposure to iron can be lethal to fish, but long-term sublethal impacts of iron require further study. Here we... more Acute exposure to iron can be lethal to fish, but long-term sublethal impacts of iron require further study. Here we investigated whether the spatial and temporal distribution (1967–2004) of two closely related species of stickleback matched the spatial distribution of iron concentrations in the groundwater.
We used the ‘Northern Peel region’, a historically iron-rich peat landscape in The Netherlands as a case study. This allowed us to test the hypothesis that niche segregation in two closely related species of stickleback occurred along a
physiological axis. Patterns in stickleback occurrence were strongly associated with spatial patterns in iron concentrations before 1979: iron-rich grid cells were avoided by three-spined stickleback (Gasterosteus aculeatus , Linnaeus 1758) and preferred by nine-spined stickleback (Pungitius pungitius , [Linnaeus, 1758]).
After 1979, the separation between both sticklebacks became weaker, corresponding to a decreased influence of local groundwater on stream water quality. The way both species changed their distribution in the field provides a strong indication that they differ in their susceptibility to iron-rich conditions. These observed differences correspond with differences in their respiration physiology, tolerance of poor oxygen conditions
and overall life-history strategy documented in the literature.
Our results exemplify how species can partition niche along a non-structural niche axis, such as sublethal iron-rich conditions. Other fish species may similarly segregate along concentration gradients in iron, while sublethal concentrations of other metals such as copper
may similarly impact fish via respiratory impairment and reduced aerobic scope.

A comparative study of fish population in Temengor Reservoir and Bersia Reservoir, Perak, Malaysia

by Zarul Hazrin Hashim

Authors: Muzzalifah Abd. Hamid, Mashhor Mansor, Zarul Hazrin Hashim and Mohd. Syaiful Mohammad

A study on fish diversity and community of two reservoirs in Hulu Gerik was carried out from August 2009 to December... more A study on fish diversity and community of two reservoirs in Hulu Gerik was carried out from August 2009 to December 2009. The two selected reservoirs were Temengor Reservoir and Bersia Reservoir. The aim of this study is to compare the community structures of freshwater fish population between these two reservoirs. A total of 15 species which comprise of six families were recorded in this study. Twelve species were recorded in Temengor Reservoir whereas 13 species were recorded in Bersia Reservoir. The best represented family in both reservoirs was Cyprinidae with eight species in Temengor Reservoir and seven species in Bersia Reservoir. Cyclocheilichthys apogon was selected for the length-weight relationship and condition factor analysis. C. apogon showed a better growth in Bersia Reservoir in comparison to Temengor Reservoir.

Impacts of climate warming on long-term dynamics of key fish species in 24 European Lakes24 European long-term data series.

by pietro volta

Jeppesen E., T. Mehner, I.J. Winfield, K. Kangur, J. Sarvala, D.Gerdeaux, M. Rask, H.J. Malmquist, K. Holmgren, P. Volta, S. Romo, R. Eckmann, A. Sandström, S. Blanco, A. Kangur, H. Ragnarsson Stabo, M. Meerhoff, A. Ventelä, M. Søndergaard, T.L. Lauridsen. Hydrobiologia. Major revision.

Fish play a key role in the trophic dynamics of lakes. With climate warming, complex changes in fish assemblage... more Fish play a key role in the trophic dynamics of lakes. With climate warming, complex changes in fish assemblage structure may be expected owing to direct effects on temperature and indirect effects operating through eutrophication, water level changes, stratification and salinisation. We reviewed published and new long-term fish data series from 24 European lakes. We found profound changes in fish assemblage composition, size and age structure during recent decades and a shift towards higher dominance of eurythermal species. The shift has occurred despite an overall reduction in nutrient loading that should have benefited the fish species typically inhabiting coldwater low-nutrient lakes and larger-sized individuals. The cold-stenothermic Arctic charr has been particularly affected and its abundance has decreased in the majority of the lakes where its presence was recorded. The harvest of cool-stenothermal trout has decreased substantially in two southern lakes. Vendace, whitefish and smelt show a different response depending on lake depth and latitude. Perch was apparently
stimulated in the north, with stronger year classes in warm years, but its abundance has declined in the southern Lake Maggiore. Where introduced, roach now seems to take advantage of the higher temperature after years of low populations. Eurythermal species such as common bream, pike-perch and shad are on the increase. The response of fish to the warming in recent decades has been surprisingly strong,
making them ideal sentinels for detecting and documenting climate-induced modifications of freshwater ecosystems.

Effects of introduction of common bream (Abramis brama) to a shallow Italian lake: dominance of small sizes-classes and deterioration in ecological state.

by pietro volta

Volta P., Jeppesen E., Leoni B., Campi B., Sala P., Garibaldi L., Lauridsen T., Winfield IJ. Biological invasions. Major revision.

Introduced non-native species are increasingly recognized as one of the main threats to biodiversity and ecosystem... more Introduced non-native species are increasingly recognized as one of the main threats to biodiversity and ecosystem functioning. We describe the population biology and life-history of the non-native fish common bream, Abramis brama (Pisces: Cyprinidae), which became successfully established in the late 1990s in Lake of Montorfano, a shallow lake in northern Italy which subsequently showed major changes in ecological state. Bream became the most abundant species and showed a remarkably short life cycle, with asymptotic length 33.5 cm, estimated mean length at first maturity 19.6 cm and total mortality rate 0.64 y-1. The diet of the bream was overwhelmingly dominated by microcrustaceans. Following bream establishment, zooplankton biomass decreased and phytoplankton biomass and the proportion of cyanobacteria increased markedly, indicating increased top-down control of zooplankton by fish. In addition, water transparency and coverage of submerged macrophytes declined and small native cyprinids disappeared. Selective removal of bream and perhaps stocking of native piscivorous could improve the ecological status of the lake.

pp’DDT and pp’DDE accumulation in a food chain of Lake Maggiore (Northern Italy): testing steady-state condition.

by pietro volta

Bettinetti, R., V. Croce, S. Galassi & P. Volta. 2006. Environmental Science and Pollution  Research 13: 59-66.

The recent invasion of roach (Pisces: Cyprinidae) in a large South-Alpine Lake.

by pietro volta

Volta P. & N. Jepsen. 2008. Journal of Limnology 67(2): 163-170.

Very recently, a common cyprinid fish species at northern latitude, the roach (Rutilus rutilus L.) has been observed... more Very recently, a common cyprinid fish species at northern latitude, the roach (Rutilus rutilus L.) has been observed in the large south-alpine Lago Maggiore for the first time. The colonization of the lake has the characteristics of an invasion. In order to investigate this new fish population, benthic multi-mesh and commercial gill nets were used to sample fish in a wide gulf in the central part of the lake (Golfo Borromeo) from February to October 2006. In total 779 roach (TL: 5.5 – 38.8 cm) were caught, aged, sexed and stomach analyzed. Fecundity was assessed by counting the eggs in ripe gonads of females of age 3 and 4. The roach have become clearly the dominant species in the catches, constituting over 70% of the biomass and 70% of the numbers caught. None of the roach exceeded 8 years in age. They grow very fast (Φ' = 2.55) and have high fecundity (Fabs = 13740 ±4700 S.D. at age 3 and Fabs = 14768 ±5642 S.D. at age 4). The diet spectrum is wide and characterized by a strong seasonality. In early spring algae (benthic and planktonic algae), benthos and detritus prevail, whereas in summer zooplankton is the most frequent food item. In autumn roach switch back to benthos and detritus. Algae occur more frequently in young specimens while zooplankton, benthos and
detritus in adults. The roach population is practically unimpacted by fishing. The minimum legal mesh size (25 mm) of gillnets, used by commercial fishermen, selects roach at the mean LT of 21.2 cm, which is over its length at maturity. The results suggest that roach established a viable population in Lago Maggiore less than a decade ago and rapidly became one of the dominant (if not the dominant) fish species. The possible consequence for the fish fauna in general and for the ecological status of the whole lake is briefly discussed.

Assessing lake typologies and indicator fish species for Italian natural lakes using past fish richness and assemblages.

by pietro volta

Volta P., Oggioni A., Bettinetti R & E. Jeppesen. 2011. Hydrobiologia 671: 227-240

In order to establish a fish-based typology of Italian lakes and identify possible reference and indicator fish... more In order to establish a fish-based typology of Italian lakes and identify possible reference and indicator fish species for each lake type, we analysed historical data on fish assemblages of all Italian natural lakes[0.5 km2 from the period prior to the major decline in water quality in the 1950s. General linear regression models showed the ecoregion and lake altitude being the best predictors of fish species richness. The number of species was significantly higher in the Alpine than in the Mediterranean
ecoregion. Among Alpine lakes, the number of fish species increased significantly with lake volume whilst decreased with altitude. In the Mediterranean lakes, none of the selected parameters was significant.
Cluster analysis of fish assemblages (presence/ absence) divided the lakes of the Alpine and Mediterranean ecoregions into four and two types, respectively. Pike (Esox lucius), rudd (Scardinius erythrophthalmus) and tench (Tinca tinca) were the
main indicator species for the small and mostly shallow lakes in both the Alpine (Type 1) and Mediterranean (Type 6) ecoregions, minnow (Phoxinus phoxinus) for the alpine high altitude lakes
(Type 2) and landlocked shad (Alosa fallax lacustris), European whitefish (Coregonus lavaretus) and burbot (Lota lota) for the large and very deep alpine lakes (Type 4). The European whitefish was the only indicator species for the deep Mediterranean lakes (Type 5). These species and associated fish assemblages may be useful indicators in future assessments of the ecological status of Italian lakes according to the European Directives (2000/60/EC and 2008/105/
EC).

Williams, J. P., J. T. Claisse, D. J. Pondella, L. Medeiros, C. F. Valle and M. A. Shane. 2012. Patterns of Life History and Habitat Use of an Important Recreational Fishery Species, Spotfin Croaker, and Their Potential Fishery Implications. Marine and Coastal Fisheries 4(1):71-84.

by Jeremy T. Claisse

Abstract Spotfin croakers Roncador stearnsii, a prized recreational catch, were collected throughout the Southern... more Abstract Spotfin croakers Roncador stearnsii, a prized recreational catch, were collected throughout the Southern California Bight, primarily as bycatch from a long-term, scientific gill-net collection effort. The maximum otolith-based age in the present study was 24 years?14 years greater than in a previous scale-based aging study. Multiple models were used to estimate mean length at age, including models that utilize larvae as well as juveniles and adults, and the model selection results suggest sexual dimorphism in growth patterns. The juvenile and adult catch per unit effort reflected a clear pattern of habitat selectivity, with fish strongly preferring soft-bottom habitats. Catches in rocky-reef areas were limited but tended to increase with water temperature. The data also suggest that spotfin croakers segregate themselves sexually during the spawning season, when recreational fishing from jetties will target males and fish caught in bays and estuaries are more likely to be spawning females. These results provide further evidence for the importance of protection and restoration efforts for estuaries and bays along this well-developed coastline. The growth of larvae captured in plankton tows in July and September 2004 was substantially faster than that of larvae sampled in May, which coincided with warmer sea surface temperatures, highlighting a potentially important relationship relating temperature (and therefore geography) and settlement success

The contribution of trophic position to mercury content of pike (Esox lucius) in small boreal lakes.

by Jonathan Grey

Verh Int Verein Limnol 2006

From introduction to fishery dominance: the initial impacts of the invasive carp Cyprinus carpio in Lake Naivasha, Kenya, 1999 to 2006

by Jonathan Grey

Journal of Fish Biology: supplement D 2007

Following the accidental introduction of the carp Cyprinus carpio into Lake Naivasha during 1999, a sustainable... more Following the accidental introduction of the carp Cyprinus carpio into Lake Naivasha during 1999, a sustainable population became rapidly established and in early 2004 became the principal species exploited in the commercial fishery. Over 9000 kg of carp were harvested from the lake between October 2005 and 2006, when fish were captured between fork lengths (LF) 200 and 800 mm (>8 kg). Diet of carp <100 mm LF was dominated by zooplankton, >100 mm LF there was a shift to benthic macro-invertebrates, with these carp feeding principally upon food resources previously unexploited by the fish community. Contrary to predictions and despite the increasing carp abundance, there has been macrophyte regeneration in littoral areas since 2004. There have been substantial increases in areal cover, with coverage in 2006 at levels not observed since the late 1980s, and significant increases in species richness. Possible reasons for this, and the significance of this carp introduction, are discussed.

The use of stable isotopes to trace small scale movements by small fish species

by Jonathan Grey

Hydrobiologia 2010

Valuable biological information can be obtained by monitoring the movement of organisms. However, the choice of... more Valuable biological information can be obtained by monitoring the movement of organisms. However, the choice of monitoring method becomes highly restricted when following small organisms (<100 mm), especially in aquatic ecosystems. Stable isotopes are being increasingly used in this respect but rarely at the local spatial scale, i.e. 10–1000 s of metres. We sought to identify movement of small fishes between a main river channel and its tributary. Little overlap in isotope baseline was detected between the two channels despite some temporal variability in δ15N of baseline indicator organisms in the main river. The individuals of two small cyprinid fish species (Leuciscus souffia and Alburnoides bipunctatus) of all the size classes (40–100 mm) caught within the tributary showed considerable heterogeneity in δ15N values. Classification and discriminant analysis on isotope-derived data distinguished two significantly different groups. Moreover, this result was supported by further sampling of fish caught in the main river (in May and December 2006). Alternative hypotheses, such as dietary differences, biological factors, temporal shifts and spatial differences in diet, did not explain δ15N variability. This application of stable isotopes at a relatively small spatial and temporal scales further demonstrates its potential as a tool for ecologists.

Status, ecology and conservation of an endemic fish, Oreochromis niloticus baringoensis, in Lake Baringo, Kenya

by Jonathan Grey

Aquatic Conservation: Marine & Freshwater Ecosystems 2008

1.
The tilapia Oreochromis niloticus baringoensis is a genetically and morphologically distinct sub-species of... more 1.
The tilapia Oreochromis niloticus baringoensis is a genetically and morphologically distinct sub-species of Oreochromis niloticus endemic to Lake Baringo, Kenya. In recent years, concern has been expressed as to its status. Recent declines in catch returns suggest the population may be threatened, with conservation action required to safeguard it.
2.
Catch returns from the Baringo fishery since 1964 have shown considerable fluctuations for all species, but especially O. n. baringoensis. From a peak of 712 t in 1970, their total catch was only 5 t in 2005, despite a 2 year period of closure in 2002 and 2003. Changes in fishery catch and relative abundance were independent of exploitation in the fishery but were significantly correlated with lake level.
3.
Few individuals were captured at lengths >250 mm, with no fish sampled >284 mm. During periods of high lake level, individuals matured at smaller sizes and were capable of growing to larger ultimate sizes. With maturity at lengths <130 mm and fishery regulations preventing removal of fish <180 mm, there was a relatively large proportion of mature fish that was below exploitation size each year (19 to 44%). In most years, the proportion of fish available for exploitation was <10%.
4.
Stable isotope analyses revealed O. n. baringoensis was reliant upon planktonic basal resources and zooplankton carbon. There was only minimal trophic overlap with other fish species in the lake, indicating little potential for competition for food resources.
5.
These data suggest that the population status of O. n. baringoensis is not threatened per se, but subject to an unpredictable and unstable environment that strongly influences their life-history traits and, ultimately, their population abundance, and should be managed accordingly.

Determining the strength of exploitative competition from an introduced fish: roles of density, biomass and body size

by Jonathan Grey

Ecology of Freshwater Fish 2011

As species introductions can result in increased resource competition for coexisting species in the receiving... more As species introductions can result in increased resource competition for coexisting species in the receiving ecosystems, the effects of increased exploitative competition for limited food resources from an introduced fish (Pseudorasbora parva) on a coexisting fish (Cyprinus carpio) were tested experimentally using a substitutive–additive design. Additive treatments revealed that the growth of C. carpio was significantly suppressed following the introduction of P. parva with the magnitude of growth suppression directly proportional to P. parva density and biomass. A substitutive treatment that tested for the effect of intraspecific competition revealed that when C. carpio were introduced at a similar biomass to P. parva, there was no significant difference in the extent of the suppressed growth. At the same density, however, the effect of C. carpio (higher biomass) on growth was significantly above that of P. parva (lower biomass). This was independent of the initial body sizes of the introduced fishes. Thus, the interspecific competition imposed by P. parva was only as strong as the intraspecific competition of C. carpio when present at a similar biomass.

Trade-off between morphological convergence and opportunistic diet behavior in fish hybrid zone

by Jonathan Grey

Frontiers in Zoology 2009

Ferox Trout (Salmo trutta) as ‘Russian dolls’: complementary gut content and stable isotope analyses of the Loch Ness foodweb

by Jonathan Grey

Freshwater Biology 2002

1. Conventional collection methods for pelagic fish species (netting, trawling) are impractical or prohibited in Loch... more 1. Conventional collection methods for pelagic fish species (netting, trawling) are impractical or prohibited in Loch Ness, U.K. To investigate trophic relationships at the top
of the Loch Ness food web, an alternative strategy, angling, provided samples of the top predator, the purely piscivorous ferox trout (Salmo trutta).
2. The gut contents of these fish provided further samples of prey-fish, and subsequent examination of prey-fish guts revealed their dietary intake, analogous to the famous nested
‘Russian dolls’. Each trophic level separated by gut content analysis provided further complementary samples for stable isotope analysis and thus information on the longer
term, assimilated diet.
3. Ferox trout exhibited considerable cannibalism to supplement a diet of Arctic charr (Salvelinus alpinus). However, conspecifics stemmed from a lower isotopic baseline in relation to charr, so ferox trout exhibited a lower trophic level than predicted (4.3) by using the d15N values. Charr displayed dietary specialisation with increasing length, and isotopic values supported by the gut data placed the charr at a trophic level of 3.5. The isotope data
also indicated that charr carbon was primarily autochthonous in origin.