| 1. |
- Andersson, Jan, et al.
(författare)
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Assessing the dynamics of the European eel stock along the Swedish west coast
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The stock of the European eel (Anguilla anguilla) has been at a critical state for the last decades, prompting strict conservation measures. This study investigates local stock dynamics along the Swedish west coast where fishing was banned in 2012. The local stock is truly marine, which is quite unique for the species. Results of ongoing monitoring programmes are presented, and options for the assessment of the status of the stock are discussed. Results show contradictory trends over time: recruitment followed the general downward trend found throughout Europe. Catch-per-unit-effort (CPUE) for eels < 37 cm appears to decrease over time, while CPUE for size-classes > 49 cm tends to increase, especially since after the fishing ban. In the absence of information on essential processes – in particular the migration into and out of the area – it is currently impossible to assess the status of the local stock (abundance, impacts), but continued monitoring will provide indicators for the further recovery of the stock after the fishing ban.
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| 2. |
- Florin, Ann-Britt, et al.
(författare)
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How old are you-Evaluation of age reading methods for the invasive round goby (Neogobius melanostomus, Pallas 1814)
- 2018
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Ingår i: Journal of Applied Ichthyology. - : Hindawi Limited. - 0175-8659 .- 1439-0426. ; 34, s. 653-658
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Tidskriftsartikel (refereegranskat)abstract
- In the Baltic, the first observation of the round goby (Neogobius melanostomus, Pallas 1814) was made in 1990. Within the past decade the species became invasive and spread rapidly throughout the Baltic Sea. Studies about the fishes potential impacts on resident species promote the need for an increasing knowledge of their basic stock structures such as growth rates, longevity and mortality, which all rely on accurate estimates of age. Former studies on the round goby have used several different age reading techniques. In this study, we compared three standard otolith preparation methods for ageing and present the best procedure for the invasive round goby. The results showed significant differences in age estimates of the same fish between the different preparation methods and between readers. The estimation of the first annulus, the first year, was the most problematic. The overall agreement was lowest when reading the whole otoliths while the best performance was achieved with sectioned and stained preparation method. Depending on method used the growth estimates also differed. The results question comparability between previous studies and highlight the importance of harmonised aging procedures for the round goby for obtaining correct estimates of population parameters such as growth rate, age at maturity, and longevity.
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| 3. |
- Sandblom, Erik, 1978, et al.
(författare)
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Physiological constraints to climate warming in fish follow principles of plastic floors and concrete ceilings
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the resilience of aquatic ectothermic animals to climate warming has been hindered by the absence of experimental systems experiencing warming across relevant timescales (for example, decades). Here, we examine European perch (Perca fluviatilis, L.) from the Biotest enclosure, a unique coastal ecosystem that maintains natural thermal fluctuations but has been warmed by 5-10 degrees C by a nuclear power plant for over three decades. We show that Biotest perch grow faster and display thermally compensated resting cardiorespiratory functions compared with reference perch living at natural temperatures in adjacent waters. However, maximum cardiorespiratory capacities and heat tolerance limits exhibit limited or no thermal compensation when compared with acutely heated reference perch. We propose that while basal energy requirements and resting cardiorespiratory functions (floors) are thermally plastic, maximum capacities and upper critical heat limits (ceilings) are much less flexible and thus will limit the adaptive capacity of fishes in a warming climate.
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