Project Results

I am excited to share some of our findings. After the aerial surveys we started to analyze all the pictures, using a specialized software to count each individual with the help of students. We analyzed more than 5000 photographs…a lot of work J but we found very interesting results, with high abundance in three main islands. As I told you before, during field work we deployed 12 VHF tags to estimate a correction factor for precise abundance estimation. That went really great, and we did statistical analysis of the data, so now I can say that we have a correction factor for Pacific harbor seals in Mexico. I´m so excited about this result. At present, we are working on a paper with all this information, and hope to publish it this year :)

During this time, we also downloaded and started with the first preliminary analysis of the SPOT satellite tags. We noticed that two tags transmitted for more than 100 days, while others just transmitted for 9 days…but all of the information is useful. Last November, I took a small course to analyze the geographic information provided by the tags. It showed that females prefer to stay close to their reproduction site with movements of 20 km, while males travel more than 50 km, mainly north of the island. During the next months we will continue with the analysis to describe their marine habitat preference and try to identify their potential distribution in the ocean. This would lead to another paper :)

About posters, talks, or papers that came out of this project, I have been working on data analyses but haven’t presented my results at any conference yet. But this month (January) I´m going to present a poster about the abundance estimation and its corresponding correction factor at the Southern California Marine Mammal Workshop. I’ll be very happy to let the people know what we have been accomplishing with respect to the Pacific harbor seals in Mexico. I also will present the results of this project at the Mexican Society for Marine Mammalogy conference this May. At last, I hope to defend my PhD dissertation this year. I will keep in touch to let you know the news about the papers, conferences, and of course my defense :)

About This Project

Pacific Harbor seals use land to give birth to pups and molt, but once they return to the ocean to forage many seals do not survive. We have been studying this subspecies in Mexico since 2008. We describe their distribution, population size, and feeding habits. The goal of this new project is to describe where seals are traveling by using satellite tags. By knowing where the seals go we can identify important areas for marine conservation.

Ask the Scientists

What is the context of this research?

We want to know where Pacific harbor seals go after they finish their activities on land. During the Summer and Fall the number of individuals on land decreases because they return to the ocean to forage. In Mexico we have no information about how far these seals travel from their cologies. We also want to know where they are foraging.

Studies of their movements are common in the northern populations where most of the individuals travel up to 30 miles around their haul-out sites. Males travel greater distances than females. We will use satellite tags to collect information on their movements and link this data with surface temperature, productivity, and depth during foraging.

What is the significance of this project?

Pacific Harbor seals are well studied in their northern distribution, but in Mexico the information is scarce. At present our group is starting to understand what’s going on with them, studying them on land. Seals inhabit mostly temperate to cold water species, so Mexico represents their southern limit, probably with suboptimal conditions. Therefore, we think it is important to know how they adapt to this conditions, thus we have extended our studies to the ocean. But this kind of study are difficult because it is not easy to see the animals underwater, that´s why I want to use satellite tags to collect geographic information and try to understand where they are looking for food and what kind of place they prefer for ocean activities. In the end, we will locate hot spots for conservation.

What are the goals of the project?

Our main goal is to travel to Todos Santos island in May 2016 to capture six Pacific Harbor seals (females and males) and deploy satellite tags. We will collect location data for 6 months to describe their movements and identify their ocean preferences with data such as depth, water temperature, and productivity. This information will support the existing proposal to establish the islands west off the Baja California Peninsula as a natural reserve that includes Todos Santos island.

We will collaborate with local fishermen to share the knowledge about the species so they appreciate the importance of harbor seals in the ecosystem. This will probably lead to better understanding of this species’ conservation and maybe they will even take tourists to watch the seals in their natural habitat.