Schiønning MK, Marcús L, Veríssimo A, et al. Sharks and skates in the Comau Fjord, northern Patagonia, Chile: an elasmobranch species checklist with biological aspects. Journal of the Marine Biological Association of the United Kingdom. 2025;105:e44. doi:10.1017/S0025315425000335
Fjord Afar
Fjords are natural wonders of the world shaped by thousands of years of ice and glacial movement. Their history in Scandinavian culture evokes wonders of mystery and magic. What does the sea contain below the cliffs that watch over it? Scientists asked this very question, but not for a fjord in Scandinavia, but rather one on the opposite side of the world, Chile.
The Chilean Patagonian fjords stretch over a massive area including 84,000 km (~17,400 miles) of coastline. This network of inlets provides critical habitat for many coastal species in the area. However, rapid population and economic growth have subjected these fjords to intense anthropogenic activity such as aquaculture and overfishing. Research on these impacts are ongoing in the Comau Fjord, but have been almost exclusively focused on stationary bottom dwelling animals. The impacts on mobile species such as fish are relatively unknown.
Even less is known about cartilaginous fish such as sharks, skates, and rays. The only data related to them includes informal communications and unpublished research on what species are present. Schiønning et al. 2025 set out to formally inventory what elasmobranch species were present and how they may be using the Comau Fjord. An establishment of what species are present can help determine how they need to be protected from ongoing human activity.
Comau Fjord Residents
The informal data prior to this study reported six species of elasmobranchs were present in the Comau Fjord. They include:
- Spiny dogfish (Squalus acanthias)
- Narrowmouthed catshark (Schroederichthys bivius)
- Bluntnose sixgill shark (Hexanchus griseus)
- Leafscale gulper shark (Centrophorus squamosus)
- Birdbeak dogfish (Deania calceus)
- Roughskin skate (Dipturus trachyderma)
Schiønning and her research team recorded those six along with three additional species:
- Broadnose sevengill shark (Notorynchus cepedianus)
- Largespine velvet dogfish (Scymnodon macracanthus)
- Yellownose skate (Dipturus chilensis)
Spiny dogfish was the most common at 70.2% of the animals sampled. The narrowmouthed catshark was second at 9.8%. Surprisingly one of the new species, the yellownose skate, was the third most common at 9.2% of the sample.
These nine species account for nearly 20% of the species richness in southern Chile. In other words roughly 46 elasmobranch species are known to live in southern Chile and nine of them were found in this single fjord. The number of species isn’t the only important data point, but also the maturity of individuals caught.
Nursery Grounds?
Several spiny dogfish, bluntnose sixgill sharks, and narrowmouthed catsharks caught during the study were juvenile or even suspected to have been born/hatched that year. This could mean the Comau Fjord is a critical nursery ground. Juveniles of these species typically do not migrate or move far due to their young age which is why we can presume they were born here. They opt for the safety provided by the fjord before moving further offshore to join adults in deeper water.
Nursery grounds for many elasmobranchs have eluded science for many years, so finding evidence of one is a big deal! Researchers were unable to confirm their suspicions, but hope future research can follow up on this lead.
Future for the Fjord
While the Comau Fjord has been well studied, this was the first elasmobranch inventory for the Chilean fjord system. The team not only found three additional species that use the fjord, but found evidence that it could be a nursery ground. Sharks, skates, and rays reach maturity late in life and produce few young that survive until adulthood. This makes them vulnerable to human impacts such as overfishing. They need to be a more critical part of the ongoing research in the fjord system as these impacts increase. Preserving this system may mean preserving their nursery grounds and therefore future populations.
I am a recent MSc graduate in marine biology from Bangor University, where I studied population dynamics of elasmobranchs off the coast of Wales. My interests lie in ecological data analysis to understand environmental processes and identify natural patterns. However, nothing beats being in the field and interacting directly with the marine life.