What’s happening out at Sea from the Napier Port

Added 8 months ago

By Napier Port

What’s happening out at Sea from the Napier Port

In our ongoing commitment to sustainability and the protection of our marine environment, Napier Port has been actively involved in a multi-year Fisheries Survey. This initiative, part of our broader efforts to safeguard local ecosystems, has recently provided valuable insights into the impact of Cyclone Gabrielle on our region. We are proud to highlight this important work and share its findings with our community.

Fisheries survey shows impact of Cyclone Gabrielle
Each year we shine a spotlight on one of our sustainability activities. Last year, our focus was on decarbonisation and initiatives by our teams to reduce the port’s carbon footprint. This year, we are highlighting one piece of work we do to protect and enhance our marine environment - the Fisheries Survey, which has also provided some insights into the impact of Cyclone Gabrielle on local fish species.

Background
During the course of the Te Whiti wharf build, material from the dredging campaign was disposed within a new consented offshore disposal area (ODA). Commercial fisheries largely rely on a bottom trawling method around and within the area, and we wanted to ensure this wasn’t disrupted during or after the wharf build. To gain a better understanding of any effects of disposal dredging on fisheries, ongoing targeted monitoring around the ODA was implemented for key benthic species including; red gurnard, English/New Zealand sole, lemon sole, sand flounder, yellowbelly flounder and brill.

Method
Surveys have been completed on a monthly basis since May 2020. Two three-hour long trawls are completed on a single day around the perimeter of the ODA. A cage designed to reduce bycatch is used, allowing smaller fish to pass through without any abrasions. Fish that are caught are then counted and measured by length. Since January 2023, we have also started weighing fish, to gain an understanding of fish condition. These surveys have been done with the support of the Fisheries Liaison Group (FLG) which includes representatives from Napier Port, commercial fishers, Fisheries Inshore New Zealand, LegaSea, Hawke’s Bay Regional Council, NZ surf casting and Freedom Divers Club. Results from this monitoring to date support that dredging has not significantly impacted fisheries surrounding the ODA.

Cyclone Gabrielle Insights
Having undertaken three years of surveys, we now have a substantial historic data set, and have been able to utilise this data to better understand the effects of Cyclone Gabrielle on these local fish stocks. The Cyclone caused a large amount of silt, debris and logs to enter the marine environment, likely smothering food sources (small benthic invertebrates), and has caused significant reductions in CPUE (catch per unit of effort) across all species targeted. These results can be seen for a 6-month period following the cyclone. Findings verify local inshore fishers concerns about significant reduction in catches. Seven months after the cyclone, following a period of Westerly (favourable) wind conditions, we have seen monitored stocks bounce back. We hope that this signals that small invertebrates that the targeted commercial species feed on have reestablished on the sea floor, and that we can expect to see catches stabilise at this higher level again.