Beautiful, beautiful data

By Danika Kleiber

I have data. This makes me ecstatic, and like any excited child I need to show off my presents before I start playing with them.

First is the GPS data. This is really, really cool. As I’ve mentioned in a previous blog post, my research focuses on the role of women in fisheries in the central Philippines. Gleaning is one of the main fishing activities for women in the coastal and island communities of Bohol Province, where I’m based. They walk in the shallows, collecting shells, sea cucumbers, octopuses, and sometimes even fish.   

We’re asking gleaners to wear GPS units as they do this.  This way we can track how much time they spend, and how far they go. Similar data has been collected for other fishing methods, but this is the first spatial data on gleaning in these communities that I know of. Below is a track of one gleaner in the community of Suba. The map is blurry, but you can see the route she takes. And that's just one hour’s worth of gleaning!

When the gleaner returned we also measured her catch so we can get fairly precise measurements to calculate catch per unit effort (or CPUE for those fisheries lingo folks).  She caught 29 shells and four itsy bitsy crabs, so one calculation of her CPUE would be 33 animals/hour. Of course you can do more with shells than just count them.  The average size of the shells may vary from community to community, so it’s also important to weigh each item.  In this case the CPUE using weight as a measure of catch was 310.5g/hour. 

We don’t have to stop there.  We can make it even more complicated — I mean, accurate!  Shells vary from species to species in how much shell they have to protect the animal inside.  The shell species found in different communities vary likely due to differences in ecological features of their intertidal areas. Total weight of shells from Jandayan Sur, one of the research sites, may not produce as much food as an equivalent shell weight from the island of Cataban, for example.  Therefore we need to directly measure meat weight, and this is where things get tricky.

Gleaners who bring us their catch wouldn’t thank us if we started smashing their hard earned catch to measure the meat weight.  To get around this we’ve been buying shells that we can smash with impunity. We take length measurements, total shell weight measurements, and then after a little smashing, meat weight measurements.  From this we can plot the relationship between total weight and meat weight like so:

Look at that beautiful positive linear relationship!  Using the equation that best fits the data I can estimate the meat weight for every aninikad (a very commonly encountered species of mollusk) I weigh.  The best part about this type of data collection is we get to eat the results.

I love gathering these numbers and I look forward to the stories they will tell about food security and gender dynamics, but there is another type of data we’re also collecting.  The beauty of working in human systems is that you can ask direct questions. I have to contend with the communication static inherent in working in a language and culture that are not my own, but the human explanations will complement and complicate the story the numbers will tell (and this is why interdisciplinary work is so freaking cool).

The most colorful answers come from questions regarding gender roles and fishing activities. My research assistants ask the respondents who is responsible for fishing and who is responsible for gleaning.  For the most part the response is that men fish and women glean (although this is clearly not a hard and fast rule, as women do fish and men do glean).  Then they get to ask why, and this is where things get really interesting. 

Often the answer has to do with women’s domestic roles precluding fishing activities, or women’s fear of waves and water.  But hands down my favorite answer came from a woman who declared to my research assistant Jay that “women can’t fish, because when they dive, their butt floats.” I snorted into my squid adobo when I heard this, and imagined what the pearl divers of Japan (almost entirely female), and the spear fishers of Fiji (many of whom are female) would say in reply!

Danika Kleiber is a PhD student with Project Seahorse.