Cobwebs to Foodwebs by Dr. Jon Hare

collecting
fish stomach contents
from file cabinets

By Jon Hare

Field studies take a lot of effort. Think of studying fishes in an estuary – where a river meets the sea. You need the expertise to know the fishes and how to take the variety of biological samples including earbones, stomachs, and gonads. You need a boat and gear to catch fish of different sizes and habits. You need to be able to deal with weather, seasons, and the other elements of nature. You need a group of people with varying expertise committed to work together. You need funding for the project. And the field effort is just the beginning – samples need to be processed in the laboratory, data compiled and analyzed, the results published, and the data made available. Now think about how many field studies or parts of field studies never make it to those final steps of dissemination. What happens to these studies? What happens to all that effort? 

Hanson and Courtenay (2020) describe the fate of one such effort. A multi-year fish-related field program was undertaken from 1991 to 1993 to describe the structure and function of the Miramichi River and Estuary ecosystem in eastern Canada. After several years, the project ended owing to a change in priorities (and funding); the team of scientists and fishers went their separate ways. Some of the results were published – primarily around high profile species like Atlantic cod and Atlantic salmon. However, many of the samples and much of the data never made it to the dissemination stage of science. 

The study by Hanson and Courtenay is part of an effort to recover the large amounts of field data stored in old file cabinets, on floppy disks, and in unpublished theses. In their study, Hanson and Courtenay use data collected during the Miramichi Estuary program and present detailed descriptions of the stomach contents of more than 8,000 individual fish across a range of species. Through these analyses, they describe the seasonality in the estuary both in terms of fish occurrence and diet. They also identify a small shrimp species (Crangon septemspinosa – Seven-spined Bay Shrimp) as a keystone species, linking estuarine and coastal foodwebs. Although the findings are not earth-shattering, the results and data are now available for future studies, which could model foodweb dynamics in the ecosystem (e.g. using EcoPath) or document ecosystem changes over the past three decades (a neat example from Long Island Sound, USA). Field studies and the subsequent research based on field studies are essential to developing strategies for ecosystem resilience and climate adaptation and ultimately for living sustainably within the earth system. 

Original research: Hanson, J. M., & Courtenay, S. C. (2020). Data Recovery from Old Filing Cabinets: Seasonal Diets of the Most Common Demersal Fishes in the Miramichi River Estuary (Atlantic Canada), 1991–1993. Northeastern Naturalist, 27(3), 401-433. https://doi.org/10.1656/045.027.0302

Dr. Jon Hare is a scientist who works in Woods Hole, Massachusetts. His research background is fisheries oceanography and climate change impacts on marine fisheries. Check out Jon’s other sciku ‘Owls of the Eastern Ice’, ‘Varves’, ‘Signs of Spring’ and ‘Glacier Mice‘.

Signs of Spring by Dr. Jon Hare

silvery white
shadbush blossoms
swim upstream

By Jon Hare

Shadbush (Amelanchier arborea) blooms in the spring. Clusters of small white flowers appear in March through May before leaves grow. The bloom time coincides with the upstream migration of American shad (Alosa sapidissima). Millions of shad used to return to east coast rivers, but these runs are now greatly reduced because of historical overfishing, dams, and loss of habitat.

Much like salmon, shad return to rivers to reproduce after several years at sea. Unlike salmon that reproduce and die, shad go back to sea after reproducing to return to rivers in following years to reproduce again. Thus salmon are termed semelparous from the Latin semel – once, a single time. Shad are termed iteroparous from the Latin itero – to repeat.

Photo credit: NOAA Fisheries Northeast Fisheries Center.

Shadbush is also iteroparous – blooming year after year in the spring to mark the return of the shad. Recent research by Nack et al. (2019) indicates shad migration will be earlier in the season; whether shadbush will bloom earlier remains to be seen.

Original research: https://doi.org/10.1002/mcf2.10076

Dr. Jon Hare is a scientist who works Woods Hole, Massachusetts. His research background is in fisheries oceanography and climate change impacts on marine fisheries. Check out Jon’s other sciku ‘Owls of the Eastern Ice’, ‘Varves’, ‘Cobwebs to Foodwebs’ and Glacier Mice‘.

Rivers cut corners by John Norwood

Rivers cut corners

Reducing the meander

Over centuries

This poem is one of several that were inspired looking out of an airplane window. I was looking at an oxbow lake and thinking about how the river took a short cut. It is a simple reflection on what may seem static is decidedly not so with a shift of time frame. Incidentally, someone called me on this, claiming that rivers actually meander more over time. Turns out both cases can be true, but the meaning of the poem is the same either way.

Oxbow lakes are formed from curves in rivers as the water erodes the banks of bends, pinching off a loop of river that becomes an oxbow lake as it’s isolated from the main body of the river. Many rivers were channelized during the 19th century to be used as water ways, forming artificial oxbow lakes which may since have silted up or dried out. A study by Seidel et al (2017) suggests that reconnecting such oxbow lakes to the main channels might be an important measure for native species conservation and river restoration.

The name oxbow comes from the U-shaped collar that used to be used as a harness around the neck of oxen as they pulled ploughs. Other terms for oxbow lakes are loop lakes, cutoff lakes and horseshoe lakes.

Original Research: http://dx.doi.org/10.1002/clen.201600211

John Norwood is a Mechanical Engineer working with Carbon, Inc. to revolutionize how things are made. His interests include old houses, yoga, baking, cryptography, and bluegrass music. You can follow him on Twitter under the handle @pryoga

Enjoyed this sciku? Check out some of John’s other work: Universal truth, The answer is none, God may be defined, With enough data, and Squeamish ossifrage.