michaelOct 24

22-Oct-2025
#Salmon use their pituitary glands to ‘see’ when it’s time to #migrate
UMass Amherst physiologist leads team that is first to uncover how #fish sense the change of seasons

https://www.eurekalert.org/news-releases/1103013

#science #ecology #anadromous #migration

Salmon use their pituitary glands to ‘see’ when it’s time to migrate

One of the enduring ichthyological mysteries is how migratory fish know when it is time to move from their winter to summer habitats. The ability to tell when the seasons are changing is crucial for a wide range of major life events, including feeding and spawning, as well as migration. Many animals are sensitive to photoperiods, or the changing length of the days across seasons, but while scientists have a good understanding of how photoperiodism works in birds and mammals, how exactly fish recognize changes in day length has remained a mystery—until now.

EurekAlert!
CharrveinFeb 1, 2025

Genetic structure and relatedness of brown trout (Salmo trutta) populations in the drainage basin of the Ölfusá river, South-Western Iceland

Marcos Lagunas et al. PeerJ. 2023.

Recently colonized, about 10000 years ago, when #iceage #glacier retreated

Many #anadromous populations but also a few resident ones in lakes and warm mountain streams

Including #Thingvallavatn and #Úlfljótsvatn #evolution #adaptation #geothermal

CharrveinJun 13, 2024

Exploring the spawning sites and juvenile habitats of #Anadromous charr in Miðá river

Both #atlanticSalmon and #ArcticCharr are found í #Miðá

Where do the charr reside, in side streams or in slower moving water by banks?

#Snæfellsnes #Iceland #salmonid

Guðbjörg will also study their head n jaw morphology

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0300359

Diversity in the internal functional feeding elements of sympatric morphs of Arctic charr (Salvelinus alpinus)

The diversity of functional feeding anatomy is particularly impressive in fishes and correlates with various interspecific ecological specializations. Intraspecific polymorphism can manifest in divergent feeding morphology and ecology, often along a benthic–pelagic axis. Arctic charr (Salvelinus alpinus) is a freshwater salmonid known for morphological variation and sympatric polymorphism and in Lake Þingvallavatn, Iceland, four morphs of charr coexist that differ in preferred prey, behaviour, habitat use, and external feeding morphology. We studied variation in six upper and lower jaw bones in adults of these four morphs using geometric morphometrics and univariate statistics. We tested for allometric differences in bone size and shape among morphs, morph effects on bone size and shape, and divergence along the benthic-pelagic axis. We also examined the degree of integration between bone pairs. We found differences in bone size between pelagic and benthic morphs for two bones (dentary and premaxilla). There was clear bone shape divergence along a benthic–pelagic axis in four bones (dentary, articular-angular, premaxilla and maxilla), as well as allometric shape differences between morphs in the dentary. Notably for the dentary, morph explained more shape variation than bone size. Comparatively, benthic morphs possess a compact and taller dentary, with shorter dentary palate, consistent with visible (but less prominent) differences in external morphology. As these morphs emerged in the last 10,000 years, these results indicate rapid functional evolution of specific feeding structures in arctic charr. This sets the stage for studies of the genetics and development of rapid and parallel craniofacial evolution.

CharrveinApr 5, 2024

Our students presenting at

Icelandic ecological society meeting

Andreas Guðmundsson n co
Ants in geothermal areas

Kenedy Williams- adaptive evolution in charr

Guðbjörg Jónsdóttir- teeth trait diversity in sympatry

#evolution #arcticcharr #ants #lake #anadromous #geothermal

https://nordicsocietyoikos.glueup.com/event/icelandic-ecological-society-meeting-2024-98193/#conference-programme

Icelandic Ecological Society meeting 2024 | Nordic Society Oikos

The annual meeting of the Icelandic Ecological Society (VistÍs) will be held in Reykjavík, on April 5, 2024.

Glue Up
Show threadES MichelsonNov 21, 2023

#ClimateDiary -
By the way that before/after #Redwood fire recovery image from Big Basin is from a publicly accessible web cam at https://phenocam.nau.edu/webcam/sites/santacruz2
It's updated daily.
The video of this year's symposium is for you if you're interested in #ForestEcology, #anadromous #fish and more!
https://www.youtube.com/watch?v=DtdmH3KCU8s

If you're friends with the Santa Cruz Mountains Bioregional Council, please invite them to join #Mastodon.
#SantaCruz #SantaCruzMountains

The PhenoCam Network

The Phenology Network