N.H. Sea Grant Development Project Completion Report

Today’s date:

Project number: M/D‐1503

Project title: Effects of on the oxygen consumption rate of juvenile lumpfish (Cyclopterus lumpus) in the laboratory

Project initiation date: 5/28/2015

Project completion date: 12/31/2015

N.H. Sea Grant funds: $7500

Principal investigator: W. Huntting Howell

Affiliation: Dept. of Biological Sciences (DBS)

Associate investigator(s) and affiliation(s): Jenna Rackovan, DBS graduate student

Technicians and affiliations:

Partner(s) and affiliation(s) (List any collaborators, sponsors, industry partners, municipalities, etc., associated with this project): NOTE: For each partner, include SCALE (local, state, regional, national, international) and TYPE (gov’t, NGO, industry/business, academic institution, other)

Brief project overview/abstract: The lumpfish (Cyclopterus lumpus) is a commercially important species in Iceland and the Netherlands, where it is fished for which is used for caviar. More recently, studies have shown that lumpfish juveniles are useful ‘cleaner ’ in the Atlantic aquaculture industry. In this role, they prey on, and remove, damaging sea lice from the salmon. Despite the importance of the species for roe and as , little is known about its ecology and physiology. This study is examining how one environmental variable (salinity) impacts the oxygen consumption of juvenile lumpfish. Results will assist the placement of salmon and/or sea farms that wish to use lumpfish as cleaners, along salinity concentration gradients. To determine how salinity impacts the oxygen consumption of juvenile lumpfish, juveniles were exposed to five salinity treatments (10, 15, 20, 25, 30 ppt) and oxygen consumption rates were measured. This was repeated 14 times, for a total of 70 trials. Standard metabolic rates (SMR) were calculated using SMR = (V*∆Cwo2)/ (∆t*Mf), where ∆Cwo2 is the slope of the decrease in dissolved oxygen, V is the volume of the respirometry chamber, ∆t is the change in time, and

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Mf is the mass of the individual fish. Preliminary results showed that individuals had a significantly (p=0.009) higher metabolic rate at 20 and 25ppt.

Objectives: The objective of this study was to examine the effect of environmental salinity on the oxygen consumption rate of juvenile lumpfish. Specifically, to investigate the possibility of using lumpfish as a method of controlling sea lice in low salinity finfish aquaculture locations.

Brief project overview/abstract: The lumpfish (Cyclopterus lumpus) is a commercially important species in Iceland and the Netherlands, where it is fished for roe which is used for caviar. More recently, studies have shown that lumpfish juveniles are useful ‘cleaner fish’ in the Atlantic salmon aquaculture industry. In this role, they prey on, and remove, damaging sea lice from the salmon. Despite the importance of the species

for roe and as cleaner fish, little is known about its Fig. 1. Male lumpfish caught off New ecology and physiology. This study is examining how one Hampshire coast environmental variable (salinity) impacts the oxygen consumption of juvenile lumpfish. Results will assist the placement of salmon and/or sea trout farms that wish to use lumpfish as cleaners, along salinity concentration gradients. To determine how salinity impacts the oxygen consumption of juvenile lumpfish, juveniles were exposed to five salinity treatments (10, 15, 20, 25, 30 ppt) and oxygen consumption rates were measured. This was repeated 14 times, for a total of 70 trials. Standard metabolic rates (SMR) were calculated using SMR = (V*∆Cwo2)/ (∆t*Mf), where ∆Cwo2 is the slope of the decrease in dissolved oxygen, V is the volume of the respirometry chamber, ∆t is the change in time, and

Mf is the mass of the individual fish. Preliminary results showed that individuals had a significantly (p=0.009) higher metabolic rate at 20 and 25ppt.

Project methods and findings: Collection of adults for brood stock began on April 11, 2015 and ended June 5, 2015. During this time, we made >90 individual sets of 300’ long, 8” mesh monofilament gillnets. All sets were made subtidally along the New Hampshire coast. Nets were soaked for 18‐24 hours. A total of only 7 adult lumpfish (all males) were caught (Fig. 1). Because we did not have sufficient brood stock to produce and raise juveniles, we collected wild juveniles off the UNH marine research pier in July and August of 2015. Wild juveniles (Fig. 2) ranged from 15‐35 mm in length, and were kept in 6 separate, flowing seawater 10 liter tanks in the laboratory (Fig. 3). Juveniles were fed daily (frozen brine shrimp, frozen Mysid shrimp, and some white worms). The salinity of the filtered seawater in the juvenile holding tanks in the laboratory was always ≥ 30 ppt. Prior to testing, experimental individuals were moved into smaller volume

2 containers, and acclimated to the desired test salinity by slowly adding de‐ionized fresh water over a 6‐ hour period to represent a tidal cycle. Temperature was kept at approximately 17°C with a heater/chiller in a water bath that contains the acclimation and respiration chambers. Salinity was monitored using a YSI (Yellow Springs Instrument) professional plus. Once juveniles had been acclimated to the test salinity they were transferred into a small glass chamber (approximately 600‐750 ml) containing seawater at the desired salinity. The glass chamber was plugged with a rubber stopper through which a

Venier oxygen probe and temperature probe extended. Each experiment lasted for approximately 30 minutes. After the 30 minute trial, the fish were then transferred into another 10 liter tank with their test salinity where they were observed for another week. Oxygen consumption rates were measured at 5 different (10, 15, 20, 25, 30 ppt) with the 30 ppt treatment considered the control. Each salinity was tested twice Fig. 2. Wild‐caught juvenile lumpfish on the same day, and each salinity was repeated with 14 separate individuals, for a total of 70 fish throughout the experiment. In addition to measuring oxygen consumption, the behavior of fish in the experimental chambers was observed closely. The fish were largely stationary, and signs of stress (e.g. rapid respiration rate) were never observed. Because of this, fish were held at their test salinity for one week, and then gradually returned to ambient salinity. This long term holding for one week, at sometimes low salinity, indicated the fish were more tolerant of low salinity than we expected. When fish were held at 5, 10 and 20ppt for a week, only 1 of 14 fish died at each salinity. Two of the 14 fish died in the 15 and 25ppt. Only 5 fish were exposed to 0ppt, and all died within 28hrs. Mean standard metabolic rates ranged from about 0.05 to 0.07. Preliminary results showed that individuals had a significantly (p =0.009) higher metabolic rate at 20 and 25ppt (Fig. 4). However, individuals did not seem to be visually stressed in any of the salinity treatments.

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Fig. 3. Ten liter chambers used to acclimate juvenile lumpfish.

Figure 4. Effects of salinity on the standard metabolic rate of juvenile lumpfish

Accomplishments (Accomplishments are the key actions, activities or products resulting from Sea Grant projects. They are distinct from impacts in that they reflect ongoing activities or key results that may not yet have had a significant economic, societal and/or environmental benefit but lay the foundation for such a benefit. Accomplishments may evolve into impacts in the future.):

Impacts (Impacts are significant economic, societal and/or environmental benefits of a project): NOTE: Include data to validate the impact if possible

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Preliminary results indicate that lumpfish are euryhaline, able to tolerate salinities as low as 5 ppt and as high as 30ppt. Although more work needs to be done, this suggests that lumpfish could function well as cleaner fish in finfish operations occurring over a wide range of salinities.

Economic benefits realized to date (businesses retained or created, jobs retained or created, market and non‐market economic benefits): NOTE: Please quantify and provide supporting data if possible

None.

Tools, technologies or information services resulting from this project that are being used to improve ecosystem‐based management (i.e., products that address the management of land, water and living resources in coastal areas, for example that reduce contaminants that harm coastal ecosystems and seafood consumers; that track changes in ecosystem processes, biological responses and conditions, etc.):

None.

Related grants and contracts (Other grants and contracts that funded this project or that were obtained as a result of this project):

None as yet.

Publications: NOTE: Please cite and attach PDF or send a hardcopy, or provide possible title, authors, journal and status if not yet published.

Presentations, with published abstract citation if applicable: NOTE: For presentations please include number of attendees.

Rackovan, J. 2015. Effects of salinity on juvenile lumpfish (Cyclopterus lumpus) and their distribution in the Great Bay , New Hampshire. Amer. Fish. Soc. 2015 annual mtg., Portland, OR.

Awards:

None.

Additional information:

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