As the sun set Friday, Matt Pelikan and Molly Jacobson got to work. They hung sheets and lights between the trees at Long Point Wildlife Refuge to attract moths and other nocturnal insects. As creatures landed on the white fabric, the duo photographed them to add to a community database.

This was the start of the third annual Bioblitz run by BiodiversityWorks and the Trustees of Reservations, which ran until Saturday evening.

A bioblitz is an event that invites the general public to find and record as many species as possible. Participants are often encouraged to log their findings on citizen science websites such as iNaturalist.

Matt Pelikan uses a white sheet to catalogue moths and other insects. — Hailey McLaughlin

Mr. Pelikan, program director for Martha’s Vineyard Atlas of Life, a project working to document the biodiversity of the Island, said that Long Point was a natural choice for the bioblitz.

“It’s really a spectacular property that’s known for having a wide range of habitats and a wide range of biodiversity,” Mr. Pelikan said. “Because Long Point is an exceptional place, it was the first place we decided to do a bioblitz.”

This weekend, about 20 people helped catalog hundreds of plants and animals that live in the 632-acre refuge.

Sharon Britton said she has taken part in a number of bioblitzes over the years.

On the prowl for science. — Hailey McLaughlin

“You learn a lot of things and you get to hang around a lot of very experienced people,” she said.

While some took to the forest or sand plains to look for species, others headed for the water, including Sam Gurney, Rich Couse and Will Hamsom. The three met near the shore of Tisbury Great Pond Saturday morning to conduct a survey of the aquatic wildlife. As the group walked along the shore, Mr. Couse, program director for Natural Neighbors, bent over to take a photo of a horseshoe crab shell.

“For iNat, it doesn’t matter if it is alive or dead, because it is evidence of life,” he said.

Mr. Gurney, a second year intern with BiodiversityWorks, and Mr. Couse waded into the pond with a seining net held between them. The two pulled the net as they walked through the water, turning it sideways to reveal fish, crabs, shrimp and comb jellies. The two rolled up part of the net to get a better look at their bounty.

Fireflies are abundant this year. — Hailey McLaughlin

“I love these. They can get this vibrant blue color when mating,” Mr. Gurney said as he picked a sheepshead minnow from the net, “They can go in salt and fresh water, which is why they go so well here.”

The trio worked their way along the shore of Middle Point Cove, braving the marshy bottom to capture and release fish species that burrow in the mud. They stopped to place species in a jar of pond water and take photographs before returning them to the water.

According to Mr. Pelikan, almost 300 species were identified during the bioblitz, although results are still being compiled as of Monday afternoon. Of those species, there were a number of unusual wasps observed in the sand plains. Ms. Britton also found a species of fly from a subfamily that is not commonly observed on the Island.

“I think it went very, very well,” Mr. Pelikan said, “It was a very successful day in terms of the volume of data.”