Low abundance and diversity of seabirds and cetaceans in the Bay of Bengal

This blog is a little a-typical for the Sigur Nature Trust because it is about a paper on marine birds. Notice how fast the fisheries are crashing in the Bay of Bengal. It should prompt immediate better management. Apparently, it does not. Too bad for our food safety.

Seabirds are top predators and an important component of the marine food web, and their abundance and diversity can indicate the condition of marine fisheries, upon which millions of people depend. According to the Central Marine Fisheries Research Institute, marine fish catch from India declined 9% in 2018 compared to the previous year, mainly due to reduced catch in West Bengal, Karnataka and Maharashtra (https://www.financialexpress.com/market/commodities/marine-fish-catch-falls-9-in-2018/1642588).

There is paucity of data on sea bird and cetacean abundance and distribution in the Bay of Bengal Large Marine Ecosystem (BOBLME). To assess the abundance and diversity of these two taxa, which are critical for the functioning of marine ecosystems, a team led by Ravichandra Mondreti and David Gremillet carried out at-sea surveys within the Bay of Bengal from 2012 to 2014 (link to paper here). The surveys were conducted from 39 vessel-based observations where all seabirds and cetaceans were recorded over a linear distance of around 4,722 km. A total of 2,697 seabirds from 17 species and 1,441 cetaceans belonging to at least 8 species were recorded. Sooty Terns Onychoprion fuscatus (n = 2,282, 85% of all birds) and Wedge-tailed Shearwaters Ardenna pacifica (n = 327, 12%) predominated, whereas cetacean numbers were dominated by Spinner Dolphins Stenella longirostris (n = 772, 54% of all cetaceans) and Indo-Pacific Bottlenose Dolphins Tursiops aduncus (n = 533, 37%). Dolphins and Pacific Bottlenose Dolphins, accounting for 93% of cetacean sightings.  

The abundance and diversity of both groups was low compared to other tropical areas. This could result from low ocean productivity caused by stratification in the Bay of Bengal, human impacts such as disturbance, overexploitation of marine resources and long line fisheries, where seabirds form a significant bycatch. There is also a paucity of breeding sites for pelagic seabirds. Therefore conservation efforts need to be stepped up in BOBLME to maintain the viability of marine ecosystem functioning.

P. Davidar

The ultimate tragedy of the commons?

Some of our colleagues and friends who are social scientists think of us conservationists as neocolonialists and/or pro-capitalists when we say that forests should be more protected. They often view forests as an ill-managed resource because for them (i) forest management is inherited from the British colonial rule, (ii) the poor need to have control over their environment and (iii) if local people do not manage their environment, other forces will.

I am originally from working class and I am systematically grieved to find myself clubbed with bad guys proposing to rip-off the poor of their scant resources. It is funny that these views often originate from fairly privileged left-wing people. Not that there is anything wrong to be left-wing and privileged. But whether from working class or more privileged extraction, there is a danger in creating a narrative on the basis of self-righteousness and paucity of data. The examples of locally protected forests that demonstrate sufficient size and ecological viability are by far too rare. We have however access to ample scientific data showing beyond doubt that the biosphere is getting destroyed at a rapid pace. If the forest was really cut for the poor, then it would be a lesser evil.

I never believed that access to forest resources would carry the poor out of poverty. In the early 1990s, it was clear to my colleague Jean-Pierre Garrigues and I, that landless laborers were working for “rich” farmers to extract manure, fodder and non-timber forest products from the forest. A simple way to “help” the poor, would have been to provide regular jobs. But even today, thirty years later, many people have lost their income because of the COVID-19 lock down: there are still daily wage workers.

Where do the resources generated by deforestation go? Thomas Picketty, the author of “Capital in the Twenty First Century”, a must-read book, may have an answer. If you look at the figure below (https://news.harvard.edu/gazette/story/2020/03/pikettys-new-book-explores-how-economic-inequality-is-perpetuated/) you can see that economic inequality has increased since the 1980s (and probably earlier). The figure shows the share of total income by the top 10%. This trend is of enormous magnitude with astounding social consequences.

It would be tempting to correlate the decrease of primary forest cover (for example here) with the increase of inequality. And I have a suspicion: like most economic activities, forest destruction may benefit the poor only marginally. This would be the ultimate tragedy of the commons.

Jean-Philippe Puyravaud