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- Bartolino, Valerio, et al.
(författare)
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Spatio-temporal dynamics of a fish predator: Density-dependent and hydrographic effects on Baltic Sea cod population
- 2017
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the mechanisms of spatial population dynamics is crucial for the successful management of exploited species and ecosystems. However, the underlying mechanisms of spatial distribution are generally complex due to the concurrent forcing of both density-dependent species interactions and density-independent environmental factors. Despite the high economic value and central ecological importance of cod in the Baltic Sea, the drivers of its spatio-temporal population dynamics have not been analytically investigated so far. In this paper, we used an extensive trawl survey dataset in combination with environmental data to investigate the spatial dynamics of the distribution of the Eastern Baltic cod during the past three decades using Generalized Additive Models. The results showed that adult cod distribution was mainly affected by cod population size, and to a minor degree by small-scale hydrological factors and the extent of suitable reproductive areas. As population size decreases, the cod population concentrates to the southern part of the Baltic Sea, where the preferred more marine environment conditions are encountered. Using the fitted models, we predicted the Baltic cod distribution back to the 1970s and a temporal index of cod spatial occupation was developed. Our study will contribute to the management and conservation of this important resource and of the ecosystem where it occurs, by showing the forces shaping its spatial distribution and therefore the potential response of the population to future exploitation and environmental changes.
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| 5. |
- Cardinale, Massimiliano, et al.
(författare)
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A centurial development of the North Sea fish megafauna as reflected by the historical Swedish longlining fisheries
- 2015
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Ingår i: Fish and Fisheries. - : Wiley. - 1467-2960 .- 1467-2979. ; 16:3, s. 522-533
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Tidskriftsartikel (refereegranskat)abstract
- Historically, to compensate for declining catches, fishers have usually shifted from species characterized by high catch rate onto less easily caught species or have moved into new fishing grounds. Such shifts are poorly documented for areas with a long history of exploitation (i.e. North Sea) as they occurred long time before the start of the regular assessments of the marine resources. The Swedish longline fisheries in the Kattegat-Skagerrak and North Sea have a long history that spans over several centuries. These fisheries have historically targeted large demersal predator fish as ling (Molva molva), cod (Gadus morhua), Atlantic halibut (Hippoglossus hippoglossus) and skates (mainly Dipturus spp.). In this study, data from the Swedish longline fisheries from 1859 to 1960 have been collated. The data show that the geographical expansion of the fishery was extensive. At the turn of the 20th century, offshore longlining became concentrated north and west of the Shetlands and Hebrides, and after the WWII, the fishery expanded to Iceland and Rockall. In the offshore fishery, CPUE for the main target species, ling, remained stable, whereas for the other species, with the exception of tusk (Brosme brosme), CPUE showed a dramatic decline over time. In contrast, in the coastal longlining fishery, severe declines were revealed for all major target species except cod. We argue that the constant search for new fishing grounds in the Northeast Atlantic reflects a dwindling resource, where the fishermen kept the catch rates of ling high by travelling to more and more distant fishing grounds. © 2014 John Wiley & Sons Ltd.
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| 6. |
- Cardinale, Massimiliano
(författare)
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A multivariate lognormal Monte-Carlo approach for estimating structural uncertainty about the stock status and future projections for Indian Ocean Yellowfin tuna
- 2019
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents a multivariate lognormal (MVLN) Monte-Carlo approach to produce Kobe phase plots and Kobe II projection matrices for range of fixed catch scenarios from the 2018 Indian Ocean yellowfin tuna reference grid of Stock Synthesis models. First, we present Kobe-phase plots for the current stock status that compare within-model uncertainty estimates for a single reference case model to the structural uncertainty estimates from a reference grid of 24 models. The Kobe phase plot results portrait a more pessimistic stock status for the reference case model (94.3% overfished) compared to the uncertainty grid of 24 Stock Synthesis model configurations (83.9% overfished), which captures a wider range of plausible outcomes along SSB/SSBMSY axis. Projections were conducted based on the 2018 reference grid models for fixed catch scenarios, ranging from 60-120% of the 2017 catch. These projections predict that a 20% reduction of current catches would is required to achieve MSY-based targets by 2027 and a reduction by at least 15% is required to prevent a severe stock collapse by 2024. Our results generally support previous findings that structural uncertainty across models is often more important to capture than the often narrower within model uncertainty, given that the grid comprise an adequate range of plausible alternative configurations of the reference case model. A potential advantage of the MVLN approach over the bootstrap and MCMC routines is that it reduces the computing time, thereby enabling rapid generation Kobe phase plots for advice during typically time constraint assessment meetings.
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| 7. |
- Cardinale, Massimiliano
(författare)
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Body temperature upon mist-netting procedures in three species of migratory songbirds at a stopover site: implications for welfare
- 2018
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Ingår i: Animal Welfare. - : Cambridge University Press (CUP). - 0962-7286 .- 2054-1538. ; 27, s. 93-101
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Tidskriftsartikel (refereegranskat)abstract
- Capturing wild birds with mist nets is very common for studying many aspects of avian biology. However, except for adrenocortical reactivity, little is known about other physiological responses to this potentially stressful procedure. Here, we focused on body temperature (Tb) in migratory songbirds, as large numbers are caught for population monitoring and studies of migratory biology. Tb is sensitive to acute stress in other vertebrates and contexts, usually showing an increase (stress-induced hyperthermia). We sampled garden warblers (Sylvia borin), whinchats (Saxicola rubetra) and barn swallows (Hirundo rustica) captured with mist nests using standard protocols at an island stopover site in the central Mediterranean during spring migration. Tb was measured within 3 min (T0), 30 min (T30) and 180 min (T180) from the time the bird hit the net, using an analogue probe inserted into the throat, and a body condition score was calculated for each bird. In the garden warbler, but not the other two species, a slight but significant reduction in Tb occurred after 180 min. In all species, the change in Tb after 3 h of confinement was positively correlated to the change in ambient temperature (Ta) but not to body condition. The mean (+/- SEM) change in Tb over 3 h was -1.68 (+/- O.16)degrees C for garden warblers, therefore within the expected range of normothermy in small birds. Such reduction in Tb is contrary to the expectation of stress-induced hyperthermia; these results suggest that garden warblers are able to modulate their body temperature and that these small changes are influenced by fluctuations in ambient temperature. Therefore, Tb might not be a good indicator of capture stress in small passerine migrants. Our results also indicate that restraint for ringing procedures is unlikely to have adverse effects on Tb regulation of migratory birds, if held within the time-frame typical of ringing operations.
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- Cardinale, Massimiliano, et al.
(författare)
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Comments on Local cod (Gadus morhua) revealed by egg surveys and population genetic analysis after longstanding depletion on the Swedish Skagerrak Coast by Svedang et al.
- 2019
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Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 76, s. 1209-1211
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Tidskriftsartikel (refereegranskat)abstract
- Svedang et al. (2018) concluded that the occurrence of locally spawned cod eggs suggests that spawning on the Swedish Skagerrak coast takes place, which belong to either a coastal subpopulation that is a remnant stock of a once much larger cod population, or a newly formed subpopulation that is now successfully inhabiting the coastal ecosystems along the Swedish Skagerrak coast. However, after carefully reviewing the results and the data presented by the authors, we were no longer convinced that the information presented provided enough evidence for a local, distinct, coastal cod population in the Swedish Skagerrak. Thus, we requested the original genotype data, which the authors kindly provided to us. This allowed us to explore the substructure of these samples further using STRUCTURE 2.3.2. Re-analysis of the data consistently rejects the existence of an independent coastal Swedish stock in contrast with Svedang et al. (2018) conclusions. We acknowledge the observation of cod spawning in the area but, based on re-analysis of the original genetic data of Svedang et al. (2018), we currently lack the scientific basis to assume the existence of established local stocks, and even less the demographic expansion of an older, relict population in the area.
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| 10. |
- Cardinale, Massimiliano
(författare)
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Effects of body condition and food intake on stop-over decisions in Garden Warblers and European Robins during spring migration
- 2017
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Ingår i: Journal für Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 2193-7192 .- 2193-7206. ; 158, s. 989-999
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Tidskriftsartikel (refereegranskat)abstract
- During migration, birds need to optimize their time and/or energy management, especially during stop-overs. Previous studies with caged birds under controlled condition support the notion that departure decisions are condition-dependent, but they did not take into account the availability or the actual intake of food. In the study reported here we investigated whether food intake interacts with condition in influencing migratory disposition in temporarily caged wild migrants. We conducted the study on Garden Warblers (Sylvia borin) and European Robins (Erithacus rubecula) at a spring stop-over site that is reached after a long non-stop flight over the Mediterranean Sea. The birds were held in cages during the day and the first night following capture, and their locomotor activity, food intake, and body mass change were recorded. In both species, food intake was positively correlated with body mass change. Body condition was positively correlated with migratory restlessness (Zugunruhe) in both species and was also negatively related to diurnal activity in Garden Warblers. Food intake was negatively correlated with diurnal activity in Garden Warblers. When only birds with low fat scores were considered, we found a positive effect of food intake on Zugunruhe in Garden Warblers. In general, European Robins consumed less food than Garden Warblers and no significant effects on Zugunruhe were found. Our results show that food intake interacts with condition in affecting migratory behavior during stop-overs. In particular, food intake may induce Garden Warblers with low fat stores at arrival to leave a stop-over site earlier. The large individual variability in food consumption supports the notion that birds vary in their capacity to refuel soon after arrival at a stop-over site. Overall, our work suggests that the decision to stay at the stop-over site or to resume migration depends on the interaction of condition, refueling capacity and rate, and migratory strategy.
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