Using a Partial Sum Method and GPS Tracking Data to Identify Area Restricted Search by Artisanal Fishers at Moored Fish Aggregating Devices in the Commonwealth of Dominica

Abstract

Foragers must often travel from a central place to exploit aggregations of prey. These patches can be identified behaviorally when a forager shifts from travel to area restricted search, identified by a decrease in speed and an increase in sinuosity of movement. Faster, more directed movement is associated with travel. Differentiating foraging behavior at patches from travel to patches is important for a variety of research questions and has now been made easier by the advent of small, GPS devices that can track forager movement with high resolution. In the summer and fall of 2012, movement data were collected from GPS devices placed on foraging trips originating in the artisanal fishing village of Desa Ikan (pseudonym), on the east coast of the Caribbean island nation of the Commonwealth Dominica. Moored FADs are human-made structures anchored to the ocean floor with fish attraction material on or near the surface designed to effectively create a resource patch. The ultimate goal of the research is to understand how property rights are emerging after the introduction of fish aggregating device (FAD) technology at the site in 1999. This paper reports on research to identify area-restricted search foraging behavior at FAD patches. For 22 foraging trips simultaneous behavioral observations were made to ground-truth the GPS movement data. Using a cumulative sum method, area restricted search was identified as negative deviations from the mean travel speed and the method was able to correctly identify FAD patches in every case.

Participatory Boat Tracking Reveals Spatial Fishing Patterns in an Indonesian Artisanal Fishery

“…Like in other cases (Daw et al, 2011;Alvard et al, 2015;Metcalfe et al, 2016), the map obtained in this study (Figure 3) clearly shows that fishing effort is not evenly distributed in the area around Badi but focused on specific fishing grounds. This type of information can be useful for spatial zonation for management planning, but should be complemented with GPS tracking data from other islands and seasons, and combined with knowledge of the informal institutions ruling the access to these fishing grounds (Deswandi, 2012;Gorris, 2016).…”

“…Another reason to include traditional interview methods in boat tracking studies is that artisanal fisheries are very diverse, and GPS setting up and data processing may require different configurations. For instance, Alvard et al (2015) worked with hand-line fishermen in Dominica, and identified three speed ranges far above the ones described in this study (Table 5), probably because in that case the boats had more powerful engines, and perhaps also for differences in the behavior of target species because they target tuna (Scombridae), marlin (Istiophoridae), and dolphinfishes (Coryphaenidae) that swim faster than the groupers. Therefore, research plans should still include procedures to characterize the fishing gears and fishermen's knowledge on how to use them.…”

“…The potential use of speed for this purpose was already pointed out by Daw et al (2011) in tracking artisanal boats from East Africa. More recently, Alvard et al (2015), presented a Partial Sum Method to automatically identify fishing activity based on speed, complementing their boat tracking data with onboard observations in a single-gear artisanal fishery from the Caribbean. In our case, working with speed-based criteria alone was not enough to quantify, because there were multiple fishing gears involved per trip, including cases where a single speed class could involve more than one gear.…”

“…Other options to document spatial distribution of fishing effort are to conduct census using patrols (Turner et al, 2015) or research vessels (Pet-Soede et al, 2001a), which require a significant budget not always available in developing countries. In this context, small and easy-to-use GPS trackers emerge as a useful tool to precisely quantify and locate fishing with high precision and relatively low cost through participatory sampling (Daw et al, 2011;Alvard et al, 2015;Metcalfe et al, 2016). In this paper, we explore the usefulness of GPS-trackers to collect information on the spatial use of fisheries resources in the Spermonde Archipelago.…”

The relative importance of subpopulation connectivity and the age distribution of mortality in exploited marine fish populations

“…Our work shows that these data are important when exploring how mature stock attributes may manifest in such populations and, consequently, that such data is needed to better inform managers whose goal is the preservation of these fish stocks. Advances in GPS (global positioning satellite) technology capable of precisely documenting catch by latitude and longitude and the increase in vessels utilizing this technology provide promising potential solutions to solving this dilemma (Omar and Hassan, 2011;Gutowsky et al, 2013;Alvard et al, 2015). Data from tagging experiments may also be used to estimate movement rates (Hampton, 1991;Arregui et al, 2006;Kurota et al, 2009) and substock structure (Block et al, 2005).…”