As aquaculture moves further offshore, the demands increase on shackles and other equipment used subsea. Rob Van Put, director global aquaculture and fishing at The Crosby Group, explains.
DALLAS, TX – The nature of fish farming means the industry is more about what is invisible beneath the surface of the water than what is above—and we are not only talking about the salmon.
Atlantic salmon, an ideal species for aquaculture, are, like other species, hatched, raised and harvested in fish farms. Much goes into their journey to the dinner plate, and none of it would be possible without the shackles, chains, and ropes that hold everything together as waves and ocean currents rage above. The trend is for the aquaculture sector to seek higher energy, cleaner water to better oxygenate stock, meaning that ancillary equipment needs to be more reliable and durable than ever before.
First, let’s look at the typical components that are employed in a floating HDPE (high density polyethylene) cage system, which are usually part of a farm grid where cages are moored together. A mooring bolt (or anchor; depending on seabed characteristics) secures the mooring line to the seabed. A series of shackles and chains connect to ropes and a connection plate, above which more shackles and chain (all supplied by The Crosby Group) connect to the buoy and cages. Sizes vary depending on the application but the largest chain near the anchor or mooring bolt is oversized and serves as a natural shock absorber as the sea state changes and keeps the mooring line at the desired angle. In the aquaculture sector, equipment is under constant tension, versus a construction environment when products are used only during a lift.
Catch of the day
Up to 600 shackles might be installed at a single aquaculture site and The Crosby Group installs up to 600km of chain in fish farms in a single year. At the time of writing, a recent installation included 485 shackles of all sizes, 222 masterlinks, 15 connection plates and 960m of long link chain. Norway, Chile, Scotland and Canada provide the majority of the world’s salmon harvest, and The Crosby Group has equipment installed at such sites globally as farmers look to different waters and climates to breed certain stocks of fish. Salmonids are an example of a species that grows faster and healthier in highly oxygenated water, which is driving the trend for farms to move out to even more remote areas.
One of the biggest potential risks that fish farms face are farmed fish escapes. This not only presents an economical problem, but farmed fish can negatively impact the surrounding ecosystem as it would represent a mixing of wild and tame genetics, potentially contaminating the wild species. This problem is the backbone of Norwegian standard NS 9415 that covers minimum requirements for site survey, risk analysis, design, dimensioning, production, installation and operation in the aquaculture industry.
Product innovation for safer, faster and easier installations
The aquaculture sector looks to The Crosby Group, the global leader in lifting, rigging and material handling hardware, for leadership on aquaculture subsea equipment. Through its Gunnebo Industries branded products, for example, unique features ensure safer, faster, and easier installation in harsh conditions, lowering the operational costs for end users. The products are manufactured and tested to, and above, the highest and most demanding standards globally to extend product life and increase safety for both personnel and the environment. Divers and, increasingly, remotely operated vehicles (ROV) are used for site inspection but, prior to installation, The Crosby Group conducts extensive subsea testing.
The company, which is enjoying double-digit growth in the aquaculture sector in 2020, sells through a global network of distributors, but constantly cultivates end user contacts, which has led to a number of notable product innovations. One company pointed to 30% time savings on installation owing to Gunnebo Industries’ sunken bolt feature on the mooring shackle that prevents rotation (unintentional loosening of the nut). The sunken bolt also reduces the risk of the shackle interacting with the net. The shackle has a spacious bow for connecting thimbles, rope and mooring / connecting plates.
The Crosby Group is set apart beyond the breadth of product and its availability close to the point of use, given its enviable status as a vertically integrated manufacturer. Vertical integration provides complete control of the manufacturing process from raw material to finished goods. This control ensures product inspection throughout the process, affording a high level of quality and consistency across all product lines. It gives a manufacturer control over a supply chain and quality of raw material source; internal engineering; product innovation and new product research and development; proximity to industry trends; control of product scheduling and manufacturing process; and much more. This traceability is increasingly important to aquaculture professionals, especially as their work takes them further and further out to sea.
Following this year’s acquisition of Feubo, a global leader in offshore mooring components for the oil and gas and wind energy sectors, The Crosby Group also includes a portfolio of premier brands that make lifting and load securement safer and more efficient, among which are Gunnebo Industries, Crosby Straightpoint, Acco, McKissick, Trawlex, Lebus, and CrosbyIP.