Diss. (sammanfattning) Umeå : Univ., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Stockholms universitet, 2005. / Härtill 4 uppsatser.

Diss. (sammanfattning)--Stockholm : University, 2004. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Univ., 2005. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitetet, 2007. / Härtill 6 uppsatser.

In this study the spawning migration activity, habitat choice (depth and temperature), foraging activity, duration of stay in the spawning site and homing-behavior was studied for anadromous pike (Esox lucius) in the wetland Österby myr, Gotland. The spawning migration was concentrated to dusk and dawn, a homing behavior was confirmed and there was no significant difference between sexes with respect to duration of stay. A difference in habitat choice and small variation in foraging activity between individuals was established.

Actinopterygian remains have been recovered from Upper Cretaceous (uppermost lower to lowermost upper Campanian) marine strata of the Kristianstad Basin, southern Sweden. This is the first record of Upper Cretaceous bony fish from the Fennoscandian shield. The fauna consists of higher taxa including Pachycormiformes (Pachycormidae), Elopiformes (Pachyrhizodontidae), Pycnodontiformes (Pycnodontidae), Aulopiformes (Enchodontidae), Ichthyodectiformes (Ichthyodectidae), and indeterminable teleost fish. The ichthyofauna comprises a relative vast number of disarticulated meso-to macroscopic bony elements (e.g. vertebrae, isolated teeth, cycloid scales, coprolites, otolithes and fin spines). All major groups are so far only recognized by a few numbers of isolated dental remains suggesting major taphonomic losses prior to preservation. The total amount of recovered bony fish elements indicates the presence of a diverse teleostean/actinopterygian fauna, although taxonomic assessments of the material are severely hampered by the low preservational degree. In addition, previous works on the vertebrate assemblage of the Kristianstad Basin have resulted in major collection biases towards larger marine vertebrates which has led to an under-representation of the actinopterygian fauna. The ichthyofauna of the Kristianstad Basin bears compositional resemblance towards those in the North American Western Interior Seaway suggesting palaeobiogeographical communication.

Diss. (sammanfattning) Uppsala : Uppsala Universitet, 2007. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2007. / Härtill 4 uppsatser.

The global mean temperature is predicted to increase by up to 5 °C during this century. For fish, being ectotherms, temperature is one of the most important environmental factors, influencing them in a number of different ways, including effects on physiological traits, timing of life history events and behavior. Atlantic salmon has been shown to grow faster after being incubated at warmer temperatures. One possible explanation for this could be that the increased incubation temperature causes decreased metabolic rates. The aim of this project was to examine whether this is true. Atlantic salmon eggs were incubated in three different temperature regimes: natural temperature conditions, heated water and a mixed temperature treatment, where eggs were incubated in increased temperature until the beginning of January and after that subjected to natural temperature conditions. Ventilation rate, a proxy for metabolism, was measured for fish from each treatment group, as well as fish length and weight. The results revealed significantly lower ventilation rates of the fish from the heated temperature treatment, but not of the fish from the mixed temperature treatment. This suggests that an increased incubation temperature causes lowered rates of metabolism in Atlantic salmon, and that the change occurs later than early January. Because of differences in size and life stage between fish from the different groups however, the results are uncertain and call for further investigations. A lowered metabolic rate will affect the fish’s behavior. A further development might therefore be to study fish survival in the wild in relation to a fish’s metabolic rate. / Jordens medeltemperatur beräknas öka med upp till 5 °C det här århundradet. För fiskar, som är ektotermer, är temperatur en av de viktigaste abiotiska faktorerna och påverkar dem på en mängd olika sätt, bland annat genom förändring av fysiologiska attribut, tidpunkter för steg i livscykeln och beteende. Lax har visats växa snabbare efter att ha blivit inkuberade i varmare vattentemperatur. En möjlig förklaring till det kan vara att en förhöjd inkuberingstemperatur orsakar en lägre metabolism. Det här projektet syftade till att undersöka om så är fallet. Ägg från lax inkuberades i tre olika temperaturförhållanden: naturliga temperaturförhållanden, förhöjd temperatur och en blandad temperaturbehandling, där ägg inkuberades i förhöjd temperatur till början av januari, varefter de utsattes för naturliga temperaturförhållanden. Gälslagsfrekvens, som fungerar som en indikator för metabolism, mättes på fisk från varje behandlingsgrupp, samt fiskarnas längd och vikt. Resultaten visade signifikant lägre gälslagsfrekvenser hos fiskarna från behandlingen med förhöjd temperatur, men inte hos fiskarna från behandlingen med blandad temperatur. Detta indikerar att en förhöjd inkuberingstemperatur orsakar en lägre metabolism hos lax, och att förändringen sker senare än tidiga januari. På grund av skillnader i storlek och livsstadier hos fiskarna från de olika grupperna är resultaten dock osäkra, vilket gör att ytterligare studier behövs. En lägre ämnesomsättning påverkar fiskars beteende. En uppföljning kan därför vara att studera fiskars överlevnad i det vilda i relation till deras metabolism.