During her 31-year career, Grampus made significant contributions to the understanding of the mackerel fishery off the United States East Coast, Canada, and the British colony of Newfoundland.

[4] The Fish Commission wanted to develop a comprehensive understanding of the migration of food fishes in the spring and autumn as they travelled to and from their summer feeding grounds, and chose to construct Grampus as a sailing ship because it wanted her to be able to remain at sea for weeks or months at a time to follow the migration continuously and investigate it completely without having to come into port for coal, as a steamer would.

In order to keep the hulls shallow, the schooners were "very wide aft, with a heavy, clumsy stern and fat counters, the run being hollowed out excessively so as to produce in the after section a series of very abrupt horizontal curves.

The ships' shallowness of hull gave them a high center of gravity that made them prone to capsizing and sinking in heavy seas, often with significant or total loss of life among their crews.

Moreover, handling the large jib required crew members to work on the bowsprit in bad weather, a dangerous practice that resulted in men being swept overboard and drowned.

[2] Referring to shipbuilding in New England, the report added, "Nearly all of the fishing vessels recently built are deeper than formerly, and embody other features that characterize the Grampus.

[8] A laboratory was situated just aft of the well;[9] it contained closet space and shelving to hold specimens in jars of alcohol, medicines, the ship′s library of over 100 volumes,[10] fishing gear, and signal gun equipment.

Fish Commission Captain J. W. Collins,[24] Grampus's hull was constructed at Noank, Connecticut, by Robert Palmer & Sons, which launched her on 23 March 1886.

[27][29] After a week on the fishing grounds without finding a single tilefish[30] – prompting Collins to propose that the species was at least locally extinct[30] – Grampus set course for Woods Hole, arriving there on 24 August 1886.

[32] With her new windlass installed, she departed Gloucester on 22 September for a cruise to La Have Bank and Roseway Bank in the North Atlantic Ocean south of Nova Scotia, Canada, and Seal Island Ground in the Gulf of Maine to collect live cod and halibut for return to Woods Hole for study and propagation, i.e., fish culture work.

[34] She had little success in her primary objective, finding that cod and halibut caught in deep water died soon after being placed in her well, apparently because of the rapid change in pressure and temperature as they were hauled to the surface.

[38] Grampus made a single-day voyage to visit the mackerel-fishing fleet in the western part of Vineyard Sound off Gay Head, Massachusetts,[25] then was engaged until March 1887 in voyages to collect spawning cod and investigate the fisheries in the Gulf of Maine, Massachusetts Bay, and Vineyard Sound, finding some success in bringing cod back alive in her well to Woods Hole, although over 95 percent of fish still died in the well.

[44] Late in the 1888 fishing season, she investigated the mackerel fishery between Nantucket and Virginia,[47] and she collected brood cod during October and the first half of November 1888.

[49] Grampus departed Woods Hole on 14 January 1889, arrived at Key West, Florida, on 27 January 1889, and began operations in the Gulf of Mexico to study the red snapper fishery on the continental shelf off the west coast of Florida in waters 90 to 300 feet (27 to 91 m) deep, continuing these operations until 27 March 1889 and battling a great deal of stormy weather to conduct her investigation.

[52][53] In September 1889 she began collecting cod eggs off Massachusetts for the Bureau of Fisheries station at Gloucester, continuing that work until the following spring.

[54] From 3 July to 25 August 1890, she resumed the work of recording water temperatures and weather off southern New England she had begun in the summer of 1889, this time joined in the effort by the United States Coast and Geodetic Survey survey steamer USC&GS George S. Blake and observers stationed aboard the Nantucket South Shoals Lightship.

[57][58] On 5 September 1891, Grampus was on a voyage from Hyannis, Massachusetts, to Woods Hole with U.S. Commissioner of Fisheries Marshall McDonald and his wife and daughter, Assistant U.S.

Fish Commissioner J. W. Collins (her former captain), and two female guests aboard when she ran aground on L'Hommidieu Shoal in Vineyard Sound during a southeasterly storm.

[59] In late June 1892, Grampus began an assignment in the lower Chesapeake Bay and the waters of the North Atlantic outside its mouth to ascertain the abundance of fishes in the region;[57] she completed this work on 20 July 1892.

[61] She spent the autumn of 1892 and winter of 1892–1893 in New England waters on fish egg collection duties and in largely unsuccessful attempts to capture live cod.

[67] She followed the fleet north to fishing grounds off the coast of New York, and then across Georges Bank to Cape Sable Island and Nova Scotia.

[42] After egg collection duty in the autumn of 1894 and winter of 1894–1895, she spent another spring in 1895 following mackerel schools, beginning her cruise on 12 April, operating from Lewes until 10 May, then following the mackerel to waters off New York, across Georges Bank and Browns Bank to Nova Scotia, to Cape North, and then briefly in the Gulf of Saint Lawrence before returning to Gloucester, where she arrived on 30 June 1895.

[42] From 8 August to late September 1895, she conducted the first investigation of mackerel abundance and behavior and associated environmental factors in the waters off northern New England, operating between the Bay of Fundy and Block Island.

[81] Between April and the beginning of July 1900, Grampus collected egg-bearing lobsters along the coast of Maine between Portland and Eastport with the assistance of a steam smack.

[85] After a chase of several days and nights off the coast of Maine, she captured two harbor seal pups which went on display in a large pool as part of the Fish Commission′s exhibit at the Pan-American Exposition of 1901 in Buffalo, New York, but they both died during the exposition′s final week.

[87] Reaching the fishing grounds that night, she began trawling on the morning of 29 July in the vicinity of 40°06′N 070°24′W / 40.100°N 70.400°W / 40.100; -70.400 at a depth of 390 to 420 feet (120 to 130 m) and two hours later brought 62 tilefish weighing a combined 700 pounds (320 kg) to the surface.

[97] Grampus completed her annual lobster collection duties off Maine in late September 1906, then was dismantled at Gloucester in anticipation of undergoing the major repairs and reconstruction advocated by the Bureau.

[98] After the completion of her repairs and reconstruction, Grampus – now referred to as an "auxiliary schooner" by the Bureau of Fisheries – began a cruise of several weeks in July 1908 to study animal life in the Gulf Stream off southern New England, collecting creatures from both deep and shallow water and taking soundings and temperature readings.

[103] Her cruise failed to discover where the southern population of mackerel went after it disappeared from the fishing grounds off Long Island each year or where the northern population went after its annual departure from the Gulf of Saint Lawrence, but Grampus did discover that weather and the presence of schools of predatory bonito had a much larger impact on the abundance of mackerel on the fishing grounds than previously suspected.

[108] In the summer of 1913 she studied the oceanography of waters from the Gulf of Maine to the Virginia Capes, discovering previously unknown scallop beds.