That’s right, folks! This week you get two of my blog posts for the price of one!

I was extremely pleased to be able to hear Dr. Castello speak on his massive study of Amazon fisheries and conservation earlier this week. Not only was his research fascinating, but Dr. Castello gave me a nice message of hope—he was involved in areas largely outside of fish conservation before diving headfirst (ha) into an extremely comprehensive review of Amazonian fishery conditions. I can certainly relate to that.

The kinds of relationships that Dr. Castello outlined were highly intriguing; in hindsight, it would seem obvious that massive deforestation and the hydrological alterations resulting from human activity would have an effect on fish populations of the Amazon, but he made it explicitly clear just how thoroughly connected the river and the riparian communities are. In this ecosystem, there is no hard line between forest and river—in fact, during the massive flooding season, fish communities actively move into floodplain regions. These areas of dense nutrition act as a refuge for fish to spawn and grow very big, very quickly. With increased deforestation and drought caused by global climate change, Dr. Castello found a direct effect on Amazon fish, to the point where one can reliably estimate a decrease in fish size and yield two years after a drought incident. He explained that in the Amazon, the effects of human disturbance are less trickle-down in nature, and much more directly affect the fish populations and the humans who rely upon them.

He went on to describe the plight of the Arapaima—a huge freshwater fish that has developed into an obligate air-breather. The peoples of the Amazon have historically relied on arapaima and other large species of fish, to the point that they have been heavily overfished. Dr. Castello outlined a fantastic case study of how invaluable traditional knowledge can be in population management situations. The local fishermen were so adept at spotting and counting arapaima that their estimates of fish population size was statistically identical to Dr. Castello’s much more rigorous and labor-intensive catch-tag-and-release approach. Working with these communities, they were able to develop and implement a management system that caused a dramatic increase in numbers of arapaima within their local floodplain lakes. It was wonderful to hear an account of real-world application of traditional knowledge and expertise.

Dr. Castello was engaging in his delivery and answered questions with obvious expertise. I am still ruminating on his methods—I’m not sure how I could adapt his research to my own thesis work, but I was nonetheless inspired.